Did the low fat era make us fat

During the 1990s, the low-fat craze changed the way Americans eat, and yet they got fatter than ever. By 2001, one-third of the American population was overweight. Here, nutritionists Marion Nestle, Walter Willett and Jeanne Goldberg, journalist Gary Taubes, and Dr. Dean Ornish, author of Eat More, Weigh Less debate the reasons behind the disparity between the low-fat message and America's obesity epidemic, and assess whether a low-fat diet is still the way to go.











You say that after 50 years of nutritional advice, the public is more confused than ever.

Well, for public confusion, you have to ask the question: To whose benefit is it to keep the public confused about nutrition? And the answer that just pops to mind is the food industry, because the food industry's mantra about nutrition advice is that there's no such thing as a good or a bad food; all foods are part of a healthful diet; and the keys to dietary advice are balance, variety, and moderation, which of course is true in theory.

But in practice, there's $34 billion worth of advertising in the United States that goes into directly selling what I call "top of the pyramid" foods, or foods that are high in fat and calories, mostly from corn sweeteners and hydrogenated fats. These are cheap foods, these are foods that are heavily marketed, and they're the foods that have come to be accustomed snacks. If you look at the basic dietary advice -- eat more fruits and vegetables, and watch your calories -- that hasn't changed in 50 years.

The food industry can't be the only culprit. Are nutritionists also to blame?

I think the problem is that diets are complex, and that when you look at dietary advice or individual studies or individual statements by food companies, they're talking about nutrients that are out of their food context, foods that are out of their dietary context, and diets that are out of the context of lifestyle. So that it's always easier to talk about single nutrients and single foods than it is to talk about complex diets that are messy and people's lifestyles. Some people exercise; some people don't. Some people smoke; some people don't. Those kinds of things make it very confusing.


Marion Nestle is chair of New York University's Department of Nutrition, Food Studies, and Public Health and the author ofFood Politics: How the Food Industry Influences Nutrition and Health. She also edited the 1988 Surgeon General's Report on Nutrition and Health. In this interview, she maintains that counting calories is the key to weight loss, but argues that it's difficult for the government and nutritionists alike to advocate eating less because of pressure from the food industry. However, she tells FRONTLINE that the food market is already becoming saturated and that she believes consumer awareness will drive the food industry to produce healthier alternatives. This interview was conducted on Dec. 10, 2003.



For nutrition and health professionals, who get a great deal of their funding from food companies, it's just as easy to say, "Well, all foods can fit into a healthful diet. I mean, eating sugar isn't bad for you." And it's not, in small quantities. But they don't really put it in its quantitative context. At this point, with obesity being such a problem in the United States and throughout the world, calories are the single most important issue to focus on, and we need to talk about calories. Nobody wants to talk about calories, because the minute you talk about calories, you have to talk about eating less, and the minute you talk about eating less, you're doing something that's bad for business.

Talk about the public health stakes. What illnesses can we prevent or ameliorate?

Well, we know what diet-related illnesses are. They're the dietary factors that raise blood cholesterol, raise blood pressure, and raise blood sugar levels, and lead to conditions such as obesity, heart disease, stroke, cancer. These are leading causes of death and disability in the United States.

If we just look at obesity alone, and the costs of overweight to the society as a whole, the estimated figure that's being thrown around is $117 billion a year. Whether it's right or not doesn't really matter. It's going to be a huge number, because the cost of type 2 diabetes alone is simply staggering to contemplate. And the idea that we're seeing type 2 diabetes in young children, where it was never seen before, or so rarely seen before that people wrote about it in the medical literature--

It used to be adult onset.

It used to be called adult-onset diabetes. And now it's childhood-onset diabetes. The cost of that terrible disease is simply impossible to contemplate. So we're not just talking about a cosmetic problem here. We're talking about healthcare costs that are being superimposed on a healthcare system that's already in very serious trouble. And it's not just here. It's everywhere in the world.

Beginning of the 20th century, the concern was that people ate enough, not about obesity.

No. If you look at the history of nutrition in this country, the United States has always produced enough food for its people. That's never been the problem. Its distribution may have been a problem. But even at the early years of this century, the most serious diet-related diseases were diseases due to under-nutrition, not having enough of the right foods, or enough variety of foods, or enough calories. That situation didn't really change until after the Second World War, when food distribution was improved and the economy improved, and people started eating more. At that point, heart disease rates started increasing and we began seeing the American Heart Association talking about what kinds of dietary changes needed to be made in order to lower heart disease risk. And they've been very successful in promoting some of those changes.

From the 50's onwards: Eat a balanced diet but eat less saturated fat.

Yeah. The early dietary advice was to try to encourage people to eat more of American agricultural products, eat a variety of foods in various groups. When the Department of Agriculture first started issuing dietary advice in the early years of this century, the advice was to choose foods from a variety of food groups. That was very uncontroversial advice. Everybody should be encouraged to eat a varied diet.

But when the situation changed and we began looking at problems related to over-consumption of foods or specific components of foods in the diet, that's when things got controversial. The American Heart Association realized early on that saturated fat was something that raised blood cholesterol levels, and blood cholesterol levels were a risk factor for heart disease -- advice, by the way, and knowledge that has not changed in the intervening years. Then the advice was to eat less of the sources of saturated fat. And then you were in political trouble, because the main sources of saturated fat in American diets are meat and dairy products, and meat and dairy products have huge lobbies that don't like the American government or heart association or any health agency telling the American public that American animal food commodities are bad for health.

Despite that lobbying, there was a shift towards using vegetable oils as opposed to animal fats.

Yes. There was a huge educational campaign to try to get people to eat less saturated fat, and that encouraged Americans to choose low-fat milk over whole milk -- that's been a big shift -- and to use vegetable oils instead of animal fats.

But what didn't accompany that message was a calorie message. Somehow calories got lost in all of that, and the individual nutrients or the individual components were taken out of their caloric context. So when fat was removed from foods, calories came in from sugars, and that didn't help the calorie situation very much.

Talk about the [changes that have been made] over that period.

… The good changes are that low-fat milk replaced whole milk. That was a good change. Vegetable oils replaced animal fats. That was a good change.

But there've been other changes that are more alarming or more disturbing in several ways. I mean, one is the replacement of milk by soft drinks and juice drinks. A tremendous lobbying effort has gone into that, and the companies that make these products have tried to encourage Americans and have been very successful in doing that, to convince Americans that soft drinks are okay to drink all day long, and that they're really okay for kids to drink all day long. That's been a big shift, and one that I think has a great deal to do with over-consumption of calories.

Other shifts have been a decrease in use of beet and cane sugars, sucrose, and its replacement by corn sweeteners. And there, the problem is that corn sweeteners are so much cheaper than sucrose, for reasons having to do with federal sugar policies. And the cheap corn sweeteners go into lots and lots and lots of food products, lowering their cost and encouraging people to buy them, because the low cost of food is an incentive to buy more of it.

You don't think this low-fat message backfired on nutritional advisors?

Well, in the late 1980s, there were two major reports that came out, identifying dietary fat as the single most important change that needed to be made in order to improve diet and health. And the reasons for that message were that some of the fat was saturated. The idea was to reduce saturated fat, but the assumption was that it was too complicated to explain all that, and that if people just reduced their fat content, the fat content of their diet, they would be improving it.

What nobody realized -- or at least I certainly could never have guessed -- was that the food industry would substitute vegetable fats for animal fats in such a profound way, and would also substitute sugars for fats, and keep the calorie content of the products exactly the same. The best example is the Snackwell phenomenon. Snackwell cookies were advertised as no-fat cookies, but they had almost the same number of calories. And in fact if you go to the store today and look at Oreo cookies, they have a reduced-fat Oreo cookie that has, I think, six calories less than the regular Oreo cookie. It's lower in fat but it's higher in carbohydrates.

Did consumers see "low fat" and miss the idea that you could get fat with other things besides fat?

Yes. I think that the "low-fat" message was interpreted as, if you had a product that was low in fat, it was good for you, without thinking of calories. Remember, nobody wants to talk about calories. Nobody wants to. The minute you start talking about fat in its caloric context, then the issue of adding sweeteners back to these low-fat products becomes very obvious. It's the same thing now with the low-carb products. They still have calories. Just because it's low-carb doesn't mean it's healthy. Just because it's low-fat doesn't mean it's healthy. It's still going to have calories, and calories are what counts.

The switch from animal fats to vegetable fats: Baking needs solid fats?

The hydrogenated fats have been with us for a long time. And we've known since the 1970s that hydrogenated fats have these trans fats in them that have roughly the same effect as saturated fat, so in effect, convert some of the unsaturated fats into saturated fats that are clearly not particularly healthy. So that's another factor.

It's taken advocacy organizations years and years of very hard work to get the Food and Drug Administration to finally agree to label trans fats, and I think that as soon as that label actually goes on the packages, we'll see the trans fats out of the food supply.

That's due for 2006?

2005 or '6. I can't remember when it is. But the companies are already starting to get them out, and you can go to the supermarket and look at food products and see lots and lots of food products advertising "no trans fats." In fact, the PepsiCo Company in its Frito Lay line, has had full page ads in The New York Times advertising these snack foods as if they were health foods: zero trans fats. Well, they've still got calories.

When it's inevitable and it's labeled, they will then try and use it as a marketing advantage.

Yes. The food industry is in trouble, in the sense that it is in a hugely competitive environment. Our country has available in the food supply 3,900 calories a day for every man, woman, and child in the country. That's roughly twice the actual population need. Food companies are beholden to stockholders. They have to grow in order to maintain their stock prices. We already have 3,900 calories a day and 320,000 different food products in the American marketplace. They can't all keep growing in that situation. So all they can do is to try to get consumers to eat their products instead of somebody else's, or to eat more in general, and they're just terrific at doing that.

And they do that not only through advertising and marketing, but also by enormous efforts to change the social environment, so that it is now socially acceptable for children to drink soft drinks in school and all day long, for babies to have soft drinks in baby bottles, and for people to snack all day long and to eat food in larger and larger portions, all of which are strategies to encourage people to eat more.

You were an adviser to a surgeon general's report?

I was the managing editor of the 1988 Surgeon General's Report on Nutrition in Health, which was one of those reports that came out identifying dietary fat reduction as a major public health priority.

When you were doing that, you were struggling with the complexity of nutrition?

We were struggling not only with the complexity of nutritional advice but also with lobbying activities from food companies, that made it impossible for the surgeon general's recommendations to say eat less of anything. So if you look at those recommendations, those recommendations are: Choose lean meat. The report couldn't say: Eat less meat. Eat a diet moderate in sugar. The report could not say: Consume fewer soft drinks. This was, after all, the Reagan administration. It was very pro-business, and it really wasn't possible to put in any "eat less" messages. That is still true. If you look on the Web sites of the major federal organizations and agencies that are dealing with the obesity epidemic, not a single one of the says, "Eat less." They all talk about activity. Now, mind you, activity's very important and I'm for it. But I think we have to talk about diet as well.

Did you think the 1992 food pyramid might make a difference? Were you then surprised that the obesity epidemic has grown through the decade since?

Remember, that 3,900-calorie-a-day figure is 600 calories higher than it was in 1970. A hundred of those calories came just between 2001 and 2002. So the food supply is expanding, putting increasing pressure on food companies to sell more in a competitive environment. That happened along with the pyramid advice.

The pyramid was meant to be released in 1991. At that point, the meat industry and the dairy industry got wind of it, didn't like where their products appeared, sort of towards the top of the pyramid, and complained so bitterly to the Department of Agriculture that the Department of Agriculture withdrew it, and redid the research and went through a year-long lobbying process that resulted in the 1992 release of the pyramid. It was already incredibly political, right from the outset.

Now, I thought that the advice would indicate that you were supposed to eat fewer meat and dairy products, and that would lower the fat content of the diet. … It never occurred to me, when the pyramid was released, that the sizes of servings of grain products in particular would increase so rapidly during the decade in the 1990s. What happened was that muffins that used to be 1 or 2 ounces expanded to 8 ounces. Soft drinks that used to be 8 ounces expanded to 64 ounces. Pretzels that were 1 ounce expanded to 7 ounces. You eat one of those 7-ounce pretzels and you've done your grain servings for the day. But most people don't realize that.

The low-fat advice makes sense, and presumably you still stand by it?

Yeah. If you're going to lose weight, the easiest place to start is with fat, because it's got twice the calories of either protein or carbohydrate. So it's a great place to begin. The second great place to begin is with soft drinks and those juice drinks, because they add calories and no other nutrients.

Why was the Atkins diet always popular, even against medical/nutrition opinion?

I think the Atkins diet is popular because it waves a magic wand and it says everything that was bad for you is now good for you, as the cartoon in the New Yorker said. And there was a cartoon just like that that showed a fairy godmother waving a magic wand. Everything that was bad for you is now good for you. So people get to eat forbidden foods. Everybody likes that.

There also must be something about the Atkins diet that increases feelings of satiety so people aren't as hungry. What the Atkins diet does is to lower caloric intake. In fact, all diets lower caloric intake. The question is whether it's healthy in the long run and whether it's sustainable. And I think the jury's still out on that one.

When you saw the cover story in The New York Times Magazine, "What If It's All Been a Big Fat Lie," what did you think?

That particular article has absolutely ruined my life as a nutritionist. I can't go anywhere without being asked about it. It attracted so much attention, and was so inflammatory in the way that it was written, that I think it's really caused the nutrition community to stand up and take notice and try to deal with it in a way that seems reasonable to people. Because there's no question that people lose weight on the Atkins diet. They absolutely do, if they follow what the Atkins diet actually says, as opposed to what it seems to say that it's saying. You can't eat everything you want and lose weight on the Atkins diet. You do have to restrict calories. But it seems easier to do it.

What that article did, I think, was to establish the debate as one that needed to be more complicated than just saying, "East less fat." It really required the nutrition community to talk about good fats and bad fats, and good carbohydrates and bad carbohydrates, and to try to educate the public about what those are. But I think all of that is a distraction from calories.

Is the article a good or a bad thing?

I think it's complicated. There's some good things about it and some bad things about it. I like debates, and I think the writer is a very good writer who had a serious message that he was trying to get across, one that he had written in a much more tempered form in Science magazine a year earlier, a much more nuanced and carefully written piece, in my view. This was much more sensationalistic.

It also put forward an alternative hypothesis: Fat is no longer the bad guy. The bad guy is carbohydrates, driving towards a new theory of glycemic index.

Right. I don't see these as new theories. I see these as part of a discussion about what you do when you're overeating calories, because it's very clear that taking in more calories than your body can handle easily deranges metabolism in all kinds of ways. That's where the "good carb, bad carb," "good fat, bad fat" issues become very important, because a very high-carbohydrate diet on top of a diet that already has too many calories is clearly very difficult for the body to handle.

The food industry is now gearing up to produce low-carb products.

Yeah. We're going to now see a huge proliferation of low-carbohydrate products. To the extent that these products help people reduce their calorie intake, I think they'll be fine. Once people find out that if they're still overeating calories, these products aren't going to work, then it's just another fad. But all of it is a distraction from what I see as the most important issue, which is to eat more fruits and vegetables and watch your calories.

A food technologist says there's four basic ingredients in food. If you take one out, you've got to put something else in. We looked at a food which was low fat, zero carbs, 80 percent protein.

And the rest of it, some sort of indigestible fiber.

Can you eat as much of that as you want?

Why would you want to? I mean, to me the issue is just extremely simple. It's: eat less, move more, and eat your fruits and vegetables. It isn't any more complicated than that.

And you know, I ask the question: To whose advantage is it to have the public confused about nutrition? Clearly it's to the advantage of the food industry, the diet industry, the diet product industry, the drug industry because they make diet drugs. The pharmaceutical industry is part of that. The healthcare industry, because overweight people are going to be unhealthy and that's going to keep doctors in business.

It gives journalists better stories, doesn't it?

Right. And journalists like to write about single nutrients because it's easier to write about single nutrients. It's very hard to talk about context. Nobody cares about context. It's complicated. It's messy. And yet in order to understand dietary issues, you need to understand the context.

Who are the healthiest people in the United States? The healthiest people in the United States are the ones who are best educated and have the most money. They choose the best foods, they eat best, they follow a whole range of healthful practices. They don't smoke. They don't drink too much alcohol. They don't take drugs. They lead active, busy, productive lives. These are the healthiest people in our country, and these are the people who need the advice least, because they're already following a whole range of lifestyle practices. One food product isn't going to change the way they live because they're already living well.

It's the large proportion of the American public that may not have enough money to buy healthful foods, that isn't as educated, that doesn't know how to interpret these messages in context, and that doesn't have the means or the time to try to figure out what to do in this confusing marketplace, that leave this huge opening for food companies to market to people who don't know how to handle that kind of marketing. When you hear on television that food companies are marketing to 6-year-olds and think that that's an appropriate thing to do, then you understand what the stakes are in this.

Some nutritionists think it was a mistake to oversimplify, that people should know about good and bad fats, good and bad carbs.

Oh, I would absolutely agree. I mean, I would say that if the Surgeon General's Report on Nutrition and Health made one mistake, it was to oversimplify. The other mistake was a political mistake, which was to not say what the report meant. The report meant: Eat fewer calories. Eat less meat and dairy products. Stop eating soft drinks and junk foods and snack foods. But it couldn't say that for political reasons. Even the slightest hint of an "eat less" message had the lobbyists in the office that was preparing the report, in force, and had the lobbyists talking to the Congress people about this dangerous report that was going to come out, that had these un-American statements about how Americans should eat less meat.

What's more important than all these details and nutrition advice?

Well, the concept is so simple, it's just laughable. It's: eat less, move more, and eat more fruits and vegetables. There is an enormous research basis for all of those. By eating less, it doesn't mean starving yourself. It just means maintaining a caloric balance that balances calories in and calories out. That's all it means. Being more active doesn't mean going to a gym every day for hours and hours. It just means moving your body from point A to point B, and doing it on a regular basis. The fruit and vegetable message is a very clear one with a very strong research basis behind it. Everything else is a distraction, and the worries about what this nutrient or that nutrient [does], or whether it's carbohydrate, fat, or protein, really doesn't matter nearly as much as the calorie issue right now.

Now, it may be that if people were maintaining a better calorie balance, that we would go back to being tremendously concerned about the balance between good fats and bad fats, and good carbohydrates and bad carbohydrates. My own advice to people who want to start maintaining caloric balance is to stop snacking, or to reduce the number of snacks, don't eat very many times during the way, stop drinking soft drinks and juice drinks completely -- that's a terrific place to begin -- and eat foods in smaller portions.

That advice is much easier to follow in theory than it is in practice, because there is so much effort to create an environment that encourages people to eat more, to eat more often, to eat in more different places, at more different times of day, and to provide foods that are so convenient that all people have to do is reach and there are the calories right there. There are wonderful research studies right now that show that people will eat more candy from a bowl that's sitting right in front of them than they will from a bowl that's 10 feet away. It's really that simple.

Characterize the obesity problem as a public health problem. Compared to 20 years ago, is this a worsening problem?

The issue of obesity became prominent just within the last 15 years. This is very recent. It's too recent for a genetic change, and so we have to look at societal changes that have taken place. So what are the main societal changes that have taken place? One, the number of calories in the food supply has gone up. Two, food marketing has increased and become more aggressive. Three, portion sizes have increased. Four, pressure -- it has become more acceptable in society for people to eat more times during the day, and in different locations where food was never seen before.

The result of this is very clear. We're seeing type 2 diabetes, which used to be called "adult-onset diabetes," in very young children. This was never seen before, or hardly ever seen before, and this will be a lifelong problem to manage, and something that will be very expensive to the country, to the people themselves, and to the healthcare system. We're seeing an epidemic of overweight that is occurring so rapidly that the Centers for Disease Control can track it from year to year, and does so on those beautiful maps on its Web site.

Does this now exceed smoking as a public health issue?

My understanding is that the problem of overweight is equivalent to the problem of smoking.

What will be the main drivers for us to change?

Well, I think we're already seeing a major society shift. We're seeing a backlash. We're seeing schools looking at the marketing practices in the schools and throwing them out. We're hearing more and more talk about regulation of advertising on children's television. We're hearing talk about tax strategies, legal strategies, elimination of farm subsidies. The lawsuits have gotten everyone's attention. But I think probably the biggest driver comes from the investment analyses that have come out, looking at the vulnerability of food companies to loss of sales if they don't change their market practices and their product mix.

How would they lose sales?

The investment analyses -- and there have now been three of them that I'm aware of: one from UBS Warburg, and J.P. Morgan in Great Britain, and another from Morgan Stanley in the United States -- all three of them say the same thing, that if people start losing weight, they're going to have to be eating less. Eating less is going to be bad for business, and it's going to be much worse for some businesses than others, so that if these food companies don't fix their product mixes to make healthier food products, and market them in a way that emphasizes the healthfulness of food products, especially those that are lower in calories, they're going to be left behind in this mass movement towards more healthful eating.

But eating less: If the average American eats 1,600 pounds [of food] a year, and they're competing for a share of this stomach, what can they do?

I don't have a very happy message for the food industry. I think they've been given a free ride in marketing for a long time now, and that free ride is now over and it should be over, particularly the marketing to children, which I think crosses an ethical line. They can't all grow in a competitive marketplace. They have argued for years that this is a matter of consumer choice. Well, consumer choice is going to come back and bite them, and that's just how the system works. If they're going to be participants in the system and they're in an over-inflated, over-abundant food marketplace in which there is far too much food for anybody to eat healthfully, some companies are going to lose and some companies are going to win. The winners are going to be the ones that can take advantage of the trends towards more healthful eating, and the losers are going to be the ones that are still marketing junk food.

But what drives us as consumers to eat less?

I'd like to see an education campaign that really tells the truth about diet and health. We never had one. Let's have one that's free of political influence, and says "eat less" when it means "eat less." That would be worth trying.

As consumers, we have our own health to worry about. We make individual choices. People need to be aware, for example, that larger portions have more calories. That may seem obvious, but it is not.

So just like people became smart about not smoking, we can solve this problem through education?

I think education is a big part of it. I think changing the environment is a big part of it. I'd like to see us try to find ways to change the environment to make it easier for people to eat more healthfully, in the same way as the environment had to change before people would stop smoking. …

Looking ahead 20-25 years, will we have confronted this obesity epidemic?

I'm always optimistic. I see so much change taking place in the society right now, and so much public awareness of what a serious problem this is and why we need to do something about it, that I can't help but be optimistic.















The public is confused about nutrition. Who is most to blame?

I think there's lots of blame to go around in this situation. First of all, the academic community has told people that they should do one thing -- say, avoid eggs, or eat lots of margarine -- when the evidence was really very minimal, in fact almost nonexistent in some situations. But yet it was presented as though this was the absolute truth. Then when science does move forward, gets some concrete evidence, sometimes it doesn't confirm what people are told, and there's obviously going to be some confusion generating out of that. Some of that's inevitable as part of the scientific process.

Of course there's also huge economic interests behind a lot of this. The huge push for high consumption of dairy products is really not based on good science, yet the public's been led to believe it's absolutely essential to have your three glasses a milk a day.

Things get reported in a preliminary state because everyone is interested.

Right. Part of the problem is that the public is interested in nutrition. The science of nutrition addresses a topic that is directly important for people, and of interest to people. Very often science is presented to the public in a way that is conclusive when in fact the science behind it is often very preliminary, very inconclusive.


Walter Willett is professor of epidemiology and nutrition at Harvard School of Public Health, a professor of medicine at the Harvard Medical School, and the author of Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating. He is also one of the principal investigators on the Nurses Health Study, one of the largest, long-term studies to look at the effect of diet on health. Willett explains how his research on the Nurses Health Study led him to become one of the USDA food pyramid's greatest critics. "The food guide pyramid that was developed in 1991 really is based on the idea that all fat is bad," he says. "This pyramid is really not compatible with good scientific evidence." In this interview, he explains the reasoning behind his revision of the food pyramid to include exercise at the base and to separate out "good" and "bad" fats and carbohydrates. This interview was conducted on Jan. 9, 2004.



The amount of disease that could be prevented through modifying one's diet?

The potential impact of healthy diet, when you combine it with not smoking and regular physical activity, is enormous. For example, our studies have shown that we could prevent about 82 percent of heart attacks, about 70 percent of strokes, over 90 percent of type 2 diabetes, and over 70 percent of colon cancer, with the right dietary choices as part of a health lifestyle. The best drugs can reduce heart attacks by about 20 or 30 percent, yet we put almost all of our resources into promoting drugs rather than healthy lifestyle and nutrition.

Do you think the government agrees with you about what's at stake?

I think the government has under-funded research in diet and nutrition. In some ways we blame the abstract government for it, but in some sense it's also the scientific community that's partly to blame for it, because we often tend to fund the novel, exciting science, the new gene discoveries, the new mechanisms of drugs, for example. Often diet and nutrition and lifestyle are perceived to be sort of pass¨È or too simple, and yet they are very important topics. There is interesting science behind it, but because it's not regarded as so novel and new, it's often neglected in scientific funding.

What caused the shift from how much you ate to what you ate?

If we look back at the beginning of the 20th century, over 100 years ago, the main problems were under-nutrition, even in the United States. During the first few decades of the last century, we discovered vitamins and minerals and the necessity for having those, and it was clear that many people were not getting enough of those critical nutrients. But we solved most of those problems, in fact, and about the middle part of the last century we started to appreciate that there was a huge epidemic of heart attacks, coronary heart disease and strokes emerging. …

Tell us about Ancel Keys, looking at different countries.

One of the ways that we appreciated that diet and lifestyle might really be important was the work of Ancel Keys, who looked at 14 different populations across Europe and Asia. What he realized was that there were some groups -- for example those living in Crete and some villages in Japan -- where heart disease rates were extremely low, only about one-tenth of those in the United States. And yet we also knew, when people moved from those environments, those lifestyles, and lived in the United States, they developed heart disease rates that were very high, just like everybody else in the United States. So that was powerful information telling us that there was something about the diet and lifestyle, way of life, that was extremely important in determining our risk of heart attacks.

Where did the idea of saturated fat come from?

The idea that saturated fat was a major underlying factor for heart disease did come about largely from the work of Ancel Keys, where he looked at various countries around the world and looked at their heart disease rates, and found that they were strongly correlated with saturated fat in the diet. However, even Keys recognized that it was difficult to point the finger totally at saturated fat, because there were many other aspects of diet and lifestyle that were different among these various population. ...

It was suggested we would do better with more vegetable oils?

Building on the work of Ancel Keys that showed that countries with high saturated fat had high heart disease rates, there were a number of detailed studies looking at, if we fed different types of fat, how would they affect our blood cholesterol? And it was found that saturated fats increased our blood cholesterol, and polyunsaturated fats from liquid vegetable oils reduce our serum cholesterol. And so in the mid-1970s, the predominant dietary advice was to replace saturated fat with polyunsaturated fat.

As it turns out, that advice was probably very good and had additional benefits beyond just those that influence serum cholesterol levels, in that [the] increase in polyunsaturated fat was probably largely responsible for the major reduction in heart disease rates we had during the '70s and early '80s in the United States. In fact, the rates of heart disease death went down by about 50 percent during that time.

The movement to get people to switch the types of fat: isn't this a heroic struggle that we should feel proud of?

Actually, I think we should be very proud of the achievements that were made during the 1970s, early 1980s, changing the type of fat in diet. We really made some very major national changes, and it did have some important benefits in reducing heart disease rates.

This low-fat dogma was incorporated into the USDA food guide pyramid in 1992?

Well, there's a little bit of complexity. It's interesting. In the '70s and early '80s, while heart disease rates were going bad, we were not talking about low-fat diets. We were talking about replacing saturated fat with a healthy fat, polyunsaturated fat. But somewhere in the mid-1980s, we lost that message. It's perhaps partly because some nutritionists felt it was too complicated to talk about different types of fat, and developed the notion we should just reduce all types of fat across the board. That was really the beginning of the low-fat, high-carbohydrate crusade.

From the beginning, people said you should limit total fat but the amount of saturated fat was less? There wasn't always a distinction?

If we go back to the 1960s, 1970s, it was really not so much even limiting total fat. It was really a replacement, and a strong belief that polyunsaturated fat was good. In fact, it really turned out to be that that was right.

[What are] examples of the types of fat?

What we were talking about when we meant replace saturated fat with polyunsaturated fat was reducing foods like butter, lard, the fat in red meat, with liquid vegetable oils and things made from liquid vegetable oils.

How is the simplification -- eat less fat -- manifest in this food guide pyramid?

Well, the food guide pyramid that was developed in 1991 really is based on the idea that all fat is bad. Therefore [if] fat is bad, and you have to eat something, carbohydrate must be wonderful. So the base of the pyramid is really emphasizing large amounts of starch in the diet. We're told we can eat up to 11 servings a day, and if that wasn't enough starch, the pyramid puts potatoes along with the vegetables, so you can have up to 13 servings a day. That's a huge amount of starch.

Where's fat?

Fat's up at the top of the pyramid, and where it says explicitly "fats and oils, use sparingly." It doesn't make any distinction about the type of fat, and it tells us to eat basically as little as possible.

From a public health standpoint, how would you characterize this pyramid?

Well, this pyramid is really not compatible with good scientific evidence, and it was really out of date from the day it was printed in 1991, because we knew, and we've known for 30 or 40 years that the type of fat is very important. That was totally neglected.

[What were the] unintended consequences? The food industry started using vegetable oils, but baking was difficult so they made a technical modification.

In some ways, we do have to credit the food industry with being responsive to what nutritionists were saying. They did believe or accepted the evidence that vegetable fats, vegetable oils, would be better than animal fats, and that really led to the development and promotion of the margarine industry and Crisco, baking fats that were made from vegetable oils. But they were made by a process called partial hydrogenation, which converts a liquid oil, say like soybean oil or corn oil, to something like margarine or vegetable shortening. As it turns out that was a very disastrous mistake, because in the process of partial hydrogenation, a totally new type of fat is formed called trans fat. The evidence has now become very clear that trans fat is far worse than saturated fat.

So when people were told to switch from butter to margarine?

Unfortunately, as a physician back in the 1980s, I was telling people that they should replace butter with margarine because it was cholesterol free, and professional organizations like the American Heart Association were telling us as physicians that we should be promoting this. In reality, there was never any evidence that these margarines, that were high in trans fat, were any better than butter, and as it turned out, they were actually far worse than butter.

People read on the label "cholesterol free."

Right. This is a good example where just focusing too much on one particular piece of the diet, one particular substance or nutrient, can really mislead us. It is true that these vegetable shortenings and margarines were cholesterol-free, and that was pushed. ... Even though these products were cholesterol-free, the trans fats in them raised our blood cholesterol much more than actual cholesterol in the margarines would have done.

"All fat is bad" led to many low-fat products, some of which had beneficial value. Talk about one example.

This campaign to reduce fat in the diet has had some pretty disastrous consequences. ... One of the most unfortunate unintended consequences of the fat-free crusade was the idea that if it wasn't fat, it wouldn't make you fat. I even had colleagues who were telling the public that you can't get fat eating carbohydrates. Actually, farmers have known for thousands of years that you can make animals fat by feeding them grains, as long as you don't let them run around too much, and it turns out that applies to humans. We can very easily get fat from eating too many carbohydrates, and the public was really directed to only focus on fat calories, when we really have to keep an eye on calories no matter where they're coming from.

With more fat-free products than ever, Americans got fatter.

Right. The reality is that during this campaign for fat-free and reduced-fat products, actual fat consumption did go down, but Americans got much fatter during this period of time. Now of course lots of things were going on at the same period in time, but I think it's highly likely this focus only on fat calories to the neglect of carbohydrate calories has contributed to this epidemic of obesity.

Is it fair to blame the food pyramid when people don't follow it anyway?

The food guide pyramid has actually had a substantial impact on the diets of Americans. If we look back compared to 20 years ago, the percentage of calories from fat in the American diet is quite a bit lower compared to earlier days. Second, there're some important indirect impacts of the food guide pyramid, in that many tens of billions of dollars of federal food policies have to be compliant with the food guide pyramid. So many programs -- for example, what's fed to young children, to pregnant mothers, to low-income families -- have to be consistent with low-fat diets. So the impact really has been, overall, substantial.

Behind the food pyramid were a collection of constituencies. Were people receptive when you raised these criticisms in the '90s?

There was not much receptivity in the 1990s, when we raised these criticisms of the food guide pyramid. It was almost an accepted religious belief that fat was bad and carbohydrates were good. Then there were lots of economic interests behind the food pyramid as well. Clearly the dairy industry is extremely well represented in the food pyramid. The beef industry is there, and it's very convenient that beef is combined along with fish and poultry and nuts and legumes. So each one of those industries can say: It's healthy to have three servings a day of our product.

What makes it so difficult to study the relation between diet and health?

The relation between diet and health is unusually complicated to study, and that's probably why we don't have all the final answers even yet. In a trial of a drug, for example, you can randomly assign people, one group to a placebo and another [group] to the new drug, and see what happens to them. But obviously you can't do that with nutrients or a whole diet very easily.

Second, we have to follow people for many years to learn all the consequences of diet, and perhaps even almost a lifetime, because some of the effects of diet may be operating during childhood and not be manifested until adult life. So there's no one simple kind of study that will give us all the truth about how diet influences our health, and we need to combine the results of many different studies to have the best and most complete picture.

One [kind] of study, for example, involves feeding small groups of people very controlled diets for short periods of time, and seeing what happens, for example, to their blood cholesterol levels. But blood cholesterol levels are only part of the picture, so we are also conducting very large studies where we enroll tens of thousands of people and follow them for many years, all the way along, finding out what they're eating, and then what happens to them in terms of their risk of heart attacks, cancers, and other conditions. And of course in those studies we need to control for many factors, like whether they smoke, how much exercise they have, their family history of various diseases. It's really only when we put those kinds of studies together with the more detailed metabolic, biochemical studies that we can have the best information about the effects of diet.

So you find out what they eat, rule out the bad things they do, and look for associations?

Right. What we do is find out what people eat through very detailed, structured questionnaires, observe what happens to them in terms of disease rates -- heart attacks and cancers, for example -- and then put these together, controlling for other aspects of lifestyle like diet and activity.

What did you notice that seemed to clash with the low-fat dogma?

When we began our studies back in the late 1970s, we expected that we would find a relationship between, say, fat intake and breast cancer, because that was almost an accepted relationship. But as the data started coming in over the years, we just did not find any higher risk of breast cancer among women who consume more fat in the diet. And the same was true for colon cancer and for heart attacks and risk of type 2 diabetes. In fact, the percentage of calories from fat in a diet has not been related to any important health outcome.

Amount of fat has no relationship to coronary heart disease?

The amount of fat had no relationship to risk of coronary heart disease, but the type of fat was extremely important.

So the advice we were getting was not just misleading but dangerous?

Right. The evidence that we accrued really suggested not only that the type of advice that people were getting was not useful, but it actually could be dangerous, because some people were eliminating the very healthy types of fat that actually reduce heart disease rates.

Certain fatty acids can dramatically reduce the incidence of cardiac arrhythmia?

One of the important findings, not just from our studies but several trials conducted by other people in Europe and also some careful animal studies, have very clearly indicated that some types of fatty acids in the diet, in particular the omega-3 fatty acids, can actually reduce the heart arrhythmias that really cause people to drop dead in the street. We call that sudden death. And that's very important because some people were eliminating those critically important fatty acids from their diet because they were told that all fat is bad. ...

Traditionally people think of carbohydrates as made up of simple sugars and complex starches. What's wrong about that?

Right. The thinking in nutrition about carbohydrates really had broken them down into two classes: sugars and so-called complex carbohydrates, which are mostly starches. ... The idea has been pushed that all forms of so-called complex carbohydrates are really the poster child of nutrients, and we should be eating them in large amounts. That's what the pyramid tells us to do. But in fact, these kinds of starches -- white bread, white rice, potatoes -- are starches that are very rapidly converted to glucose, really pure sugar, and almost instantly absorbed into the bloodstream. And these are the kinds of carbohydrates that we really should be minimizing in our diets.

A sugar rush from a potato?

Actually, careful studies have shown, demonstrated that you get a bigger rise in blood sugar after eating potatoes, a baked potato, say, than you do from eating pure table sugar.

Really!

Really.

That seems pretty extreme. Why is that?

... There are several problems with these rapid rises in blood glucose after you ingest large amounts of a rapidly digested form of carbohydrate. First of all, when the blood sugar goes skyrocketing up, the body wants to bring it back down. So our pancreas pumps out a big blast of insulin, and as a result, the blood sugar comes crashing down rapidly. In fact, in many people, after three and four hours, it overshoots and actually become a little hypoglycemic, and that rapid crashing down of blood glucose and insulin stimulates hunger. That would be no problem, except that it's often all too easy to go in the refrigerator or find a snack, and if we do that frequently throughout the day, that can add up to too many calories over weeks and months and years, and contribute to obesity.

Second, these high rises in blood glucose and insulin have a bad metabolic effect on the blood cholesterol fractions. Specifically the HDL, the good cholesterol, is driven down, and triglycerides, another type of fat in the blood that leads to heart attacks, goes up.

Third, after many years of demand for high amounts of insulin, the pancreas tends to give out. And at that point in time, we've got type 2 diabetes.

[What is the role of insulin?]

The role of insulin is to transport glucose from the blood into the cells, like into muscle or into fat cells.

What can go wrong with this system?

Well, the problem really comes about when we develop insulin resistance. And that means that the cells, like the muscle cells, become more resistant to the action of insulin transporting the glucose inside the cell. And we can become insulin-resistant in several different ways. There's some genetic component, and as it turns our, for example, many Asians tend to have more insulin resistance. Also if we have overweight or low levels of physical activity, we'll be more insulin resistant.

Many people argue the virtues of Asian diets, with a lot of white rice.

Right. The Asian diet as it's traditionally been used raises some very interesting issues in nutrition, in fact, some of the most important findings during the last several years. What we've come to realize is that if we have a higher degree of insulin resistance, then we much less well tolerate a high-carbohydrate diet.

Interestingly, in traditional Asian societies, people were very lean, very active, and therefore had low insulin resistance. They could eat large amounts of rice, even white rice, in the diet and have low heart attack rates and have low rates of type 2 diabetes. But if you take that same person, and they [now] may be living in Beijing and driving a car and watching a television, and they put on a few pounds, they're going to have much more insulin resistance. So if you take that same diet, high in carbohydrate and white rice, they will have a much worse metabolic response and much higher rates of type 2 diabetes.

If you're American and overweight, won't you be put on a low-fat diet?

If you're overweight and living in the United States, and you go to a hospital and see a dietician, almost for sure, you're going to be put on a low-fat, high-carbohydrate diet.

What's your view of that?

The problem is that that's really the wrong diet for an overweight person. Because the person is overweight, in general they're going to have quite a bit more insulin resistance and much less well able to tolerate low-fat, high-carbohydrate diet.

But fats have twice the amount of calories per gram as carbohydrates. Doesn't it make sense to push the low-calorie diet and therefore a diet low in fat?

There's been a very simplistic idea: Just because fats have more calories per ounce than carbohydrates, we should be eliminating fats or reducing fats to control our total caloric intake, in other words, to help control our weight. What's really important though is how satisfying a diet is, because we have very complex mechanisms that control our total intake of calories, and it's become pretty apparent that if we have a high-carbohydrate diet, particularly high refined carbohydrate, it makes it much more difficult to control our total caloric intake. That's probably because when we eat refined carbohydrates, we get these swings in blood glucose and insulin that lead to hunger between meals; whereas if we have a diet that's somewhat higher in fat, we tend to be more satisfied over the long run.

Is this what Dr. Atkins was saying 30 years ago?

Dr. Atkins was saying as much as 30 years ago, that if we reduce our carbohydrate intake to quite low levels, that will make it easier to control our caloric intake and thus promote weight loss. As it turns out, there is a strong element of truth in that. A number of studies in the last year have looked in a very careful way, comparing low-fat, high-carbohydrate diets with reduced-carbohydrate diets, and in general people have done better on the reduced-carbohydrate diets in terms of their weight.

Even though each ounce of fat has twice as many calories, you eat fewer calories because they're more satisfying?

Yeah. Well, first of all, this idea of how many calories per gram of fat versus how many calories per gram of carbohydrate is a little simplistic, because we almost never eat foods that are pure fat and pure carbohydrate. They come in foods as mixes, and often with a lot of fiber and a lot of water, and all of those things make a difference as well. But what is really important in the long run is how satisfying a food will be. And as it turns out, that many high-fat foods -- sometimes like meat, but even think of a handful of nuts -- are often very satisfying even though the physical amount is not very great.

One of the interesting observations in the recent studies that have compared high-fat diets with high-carbohydrate diets is that there are a lot of differences between people; that it's not that everybody loses a certain amount of weight on a reduced carbohydrate diet. Some people lose a lot of weight. Other people hardly lose any, so one of the things we have to come to understand better is the reasons why there's such a difference in response to these diets.

Talk about your food pyramid.

We've tried to put together an alternative food guide pyramid that would be based on the best available science. And of course it is a little bit challenging to boil down a tremendous amount of complex science to a simple graphic, and you really have to focus on the things that are well established and important.

Right at the bottom, we put weight control and regular physical activity, because overweight is the number one nutrition problem in the United States. Almost everyone is going to need to exercise on a regular basis if they want to control their weight over the long run. And this also is a message that all forms of calories are important.

On the next level, we put healthy forms of carbohydrate, meaning whole-grain carbohydrates and healthy forms of fat, meaning from vegetable oils, in the recognition that in most people's diet, most calories are going to be coming from some source of carbohydrate and fat. And what's really important is that those both be healthy sources.

Some of those fats have come right from the top of the other pyramid.

Right. What we've done is, we've brought some of those fats from the top of the pyramid down to the base, because healthy fats are an important part of a healthy diet.

The rest of the pyramid?

Our alternative pyramid, like the USDA pyramid, does emphasize plenty of fruits and vegetables, but we've taken potatoes out of the vegetable group. We've put legumes and nuts as a layer. If you want to be a vegetarian, those are good protein sources. But moderate amounts of poultry, fish, and nuts can also make a diet be a non-vegetarian diet and still very healthy. And up at the top we've put red meat and dairy products, dairy fat, because those are high in saturated fat. ... At the top of the pyramid, we've put foods like white bread, white rice, white pasta, and sweets as those that should be used sparingly. And that was really the base of the USDA pyramid.

Some nutritionists have criticized your pyramid as "floating on a lake of olive oil."

The formal studies that had compared a more moderate fat intake as we've suggested, with low-fat diets, have actually consistently shown that people did as well or better controlling their weight on a moderate-fat diet compared to a high-carbohydrate, low-fat diet.

Even good fats are more fattening than good carbs. So they think you're contributing to the obesity epidemic, or there's a risk of that. A tablespoon of olive oil is 14 grams of fat.

There are all kinds of beliefs about the amount of fat in a diet, tremendously strong opinions. What we really need is sound data, and the studies that have been done show that people actually end up controlling their weight at least as well, and usually better, on moderate-fat diets compared to low-fat, high-carbohydrate diets.

Is it okay to get more than 30 percent of your calories from fat?

The evidence is quite clear that it's perfectly fine to get more than 30 percent of your calories from fat, and probably, in fact, it's even better to be getting more than 30 percent of calories from fat, if it's the healthy form of fat. ...

When you look at the causes of obesity, what do you find?

The causes of obesity and the obesity epidemic in the United States are extremely complex. In fact, obesity is sort of a tip of the iceberg of tremendous social change that's been going on during the last few decades. First of all, our activity patterns have changed greatly. We have children and adults now watching on the average, about four hours of television per day, and in study after study, we've seen just the number of hours of television watching being the strongest predictor of obesity. When I was young and came home after school, we'd all go out and play, and our mothers would have to drag us in for dinner. That doesn't happen very often anymore. Often the mothers are not there. Kids are inside. The television is used as baby sitters. We've also made it dangerous and uninviting to walk to places, to walk to stores, to ride bikes in urban areas, and that's removed an important amount of physical activity from our lives as well.

So the physical activities pattern's changed, but the food environment has also changed. We have food available fast and very low-cost and very convenient, almost everywhere. The food industry has invested many tens of billions of dollars in making their products more attractive, more sweet, more salty, more sexy, more seductive in every way that they can, and we're vulnerable to that promotion, and we are eating more. So you put these two factors together -- reduction in activity, heavy promotion of food -- and you've got, not surprisingly, an epidemic of obesity.

Which we're exporting to the rest of the world.

Unfortunately, what we've created is now being exported to the rest of the world. And in almost every country, in Europe as well as Africa, Latin America and Asia, rates of obesity are climbing rapidly.

When you think about solutions, how can we proceed?

The causes of obesity are very complex, and therefore any response is going to have to be complicated and multi-faceted as well. There is no single solution to this, but we have to do many things to really solve this problem.

We've actually looked at this in a very detailed manner over the past two years in the New England states, and identified eight different areas that we have to really modify. For example, schools have to change what's served, what's promoted in schools. The healthcare providers -- physicians, nurses -- have to be providing much better and effective advice to their patients about controlling their weight. Work sites have to change. The whole food environment and what we promote to children has to be somehow modified, and we do have to protect children from these aggressive advertisements. We have to change the physical environment to make it more conducive, more attractive to bicycle to work, to destinations, not just drive places. Many other things need to be done if we're going to solve this problem, and it's time we really began.

The national obesity crisis, I mean, it's really severe. And to hear you talk about it, it sounds like it's hopeless to overcome it.

The crisis we're facing is severe, and it's getting worse. Interestingly, the full consequences won't be seen for another 30 or 40 years, because it takes that long a time for the risk of diabetes and the complication of diabetes to play out. But it's not hopeless, and I think that's the good news. There are places, if we look around the world, where people have been controlling their weight. For example, in Japan and in Sweden, women have really not been gaining weight as they've gone through midlife and gotten older, so we do need to learn more about how they're doing it.

Also in the U.S. there are many people who are controlling their weight successfully. Not everybody is going to be as successful, even if they do the same diet and do the same amount of physical activity, but many people are doing pretty well. And one piece of evidence we have is that upper-income groups actually only have about half the rate of obesity compared to lower-education groups. So it's not hopeless, but we are going to have to devote many more resources to doing this if, as a whole country, we're going to be successful. ...

The advice for so long was: Buy something that says "fat-free," or at least "low-fat" on it. All these [salad] dressings, fat free. But not necessarily a good idea?

In fact, a pretty bad idea, and that was really unfortunate that the crusade against fat really led the food industry to produce all these fat-free salad dressing products. The problem is that the fats that were in the salad dressings were the healthy fats, the ones you should be including in the diet. They were the unsaturated fats that reduce our blood cholesterol levels, and we've also seen that they reduce heart attack risk and type 2 diabetes, as well. So people were giving up these healthy fats, and what we've seen is actually an increase in risk of heart disease among people avoiding full-fat salad dressings.

Of course one of the important roles of a full-fat salad dressing is that it makes salads taste good, and we want people to be eating those vegetables. So it's not that we're telling people to gulp down bottles of salad dressing. We want them to use it on a salad and enjoy it. ...

[At] the base of your pyramid, after exercise: whole grains. Right?

Right. On the base of our pyramid, side-by-side, we put healthy fats and whole grains. And that's because we do see positive benefits in study after study, that there's lower risks of type 2 diabetes and heart disease, and probably better weight control as well, with some whole grains in the product. And that's because these carbohydrates are generally absorbed more slowly, they give less of a spike in blood glucose, and they come with a whole package of minerals, vitamins, and fiber that all have positive health benefits. ...

Some of these diets, even South Beach, for instance, say you're going to lose weight on this diet even if you don't exercise. They're not advocating that I don't exercise, but they're de-emphasizing it. You, however, are saying exercise is really central. It's the base of your pyramid, right?

Right. Exercise is absolutely essential. Even though we might think of exercising half an hour a day, and I ride my bike to work, might be quite a bit compared to the average American, it's still really pretty modest compared to what my grandfather did, who worked in the fields for 10-12 hours a day. ...

Okay now, in the great tradition of American reporting, I'll focus this all on myself again. I love nuts. My wife harasses me. She's got great advice on most things, but she says, "Don't eat nuts. Lay off nuts." You're my only hope.

Okay. Well, let me help out, because nuts are really one of the neglected health foods on American grocery store shelves. They've been given a bad rap by nutritionists because they are high in fat. Most of the calories in nuts are from fat, but it's almost all healthy fats. And what we've seen, interestingly, study after study is that people who eat more nuts do not weigh more than people who don't eat nuts. And it's probably because even a small amount can be very satisfying, and we unconsciously replace other forms of calories with the nuts when we consume them. Now of course, you can overdo any good thing. So being a little bit sensible about that is important.

What's also useful is to think of nuts not as a sort of added on snack, but as a protein source. For example, I often have it with a salad and that combination is a good meal. And there's ways to put nuts into mixed dishes and casseroles and things like that. So with a little creativity, they can really be an important part of a diet and a very healthy part of a diet.












What made you go after this topic in the first place?

Two things. I'd been reporting on salt and blood pressure, which is a huge controversy, and some of the people involved in that were involved in the advice to tell Americans to eat low-fat diets, and they were terrible scientists. These were some of the worst scientists I'd ever come across in my 20-odd year career of writing about controversial science.

I literally called up my editor and said, "I just got off the phone with so-and-so, and he's [taken] credit for getting Americans to eat less eggs and less fat. This guy's one of the worst scientists I've ever talked to, and if he was involved in this, then there's a story there." And that was it. I didn't know what the story was. I just knew there was a story.

[Was there a personal motivation?]

Bfore I did it, I was up at MIT, interviewing an economist about another story, a guy who runs a laboratory of financial engineering. He told me about being on the Atkins diet, and how effective it was. He was an Asian-American who had lost 40-50 pounds by giving up white rice, in effect.

I thought I would try it as an experiment, since I was going to write about fat and whether it really did cause heart disease and weight loss. I tried it, and it was amazing. You know, it's everything -- the 20 pounds that I'd never been able to lose, in six weeks, and I stopped exercising. It was kind of a surreal experience, and probably, in a sense, informed my opinions from there on in. I mean, after that happens, you say, "I want to know what's happening, and I want to know why."


Science journalist Gary Taubes wrote the controversial July 7, 2002 New York Times Magazinearticle, "What If It's All Been a Big Fat Lie?" which turned the spotlight onto high-fat, low carbohydrate diets. In this interview, Taubes explains his motivation for writing his piece, the science behind the low-carbohydrate diet, and the contention he faced when he published his findings. "I got crucified in a variety of publications," he says "... It was fascinating. They go after the messenger as much as the message." He is currently writing a book that is a historical and scientific exploration of the hypothesis that weight gain and chronic disease are caused by excess consumption of easily digestible and refined carbohydrates. This interview was conducted Dec. 10, 2003.



Why is it so easy for us to believe that fat is a bad dietary ingredient?

The idea is that fat has nine calories per gram, and carbohydrates and protein have four calories per gram, and somehow the theory is that the denser the calories, the more easier it is for us to eat more of them. What happened is in the '50s and '60s, when researchers started fingering fat as a cause of heart disease, the obesity researchers, the obesity community started advocating low-fat diets, which they had never done before. A low-fat diet is by definition a high-carbohydrate diet.

But you had this sort of synchronicity where you had the heart disease people saying, "Give up fat, saturated fat, for heart disease," and the obesity people started saying, "Give up fat because it must be the best diet because fat is the densest calories." They moved from there without ever testing actually either of those hypotheses, so the obesity people start recommending low-fat diets; the heart disease people are recommending low-fat diets. They have actually no idea whether it's going to cure heart disease, and the obesity people have no idea whether these diets even work. But because they believe that it's only the calories that [are] important, obviously if you give up the major source of calories in the diet, you must lose weight.

You get this hypothesis that animal fats are the worst kind of fats. That seems reasonable.

That came out of studies where you compare the fat consumption in various countries versus the heart disease rates. Basically that's what we still believe, that the Japanese have a very low fat consumption. Greeks have very low animal fat consumption. They have low heart disease rates. The U.S., Sweden, Finland have high fat consumption, they have high heart disease rates, and that's the genesis of that whole belief. "It's a worthless exercise," is what one researcher in the '50s called it. You cannot say that because fat consumption associates with heart disease, that that means it causes heart disease, because a lot of other things, for instance, associate with fat consumption. Wealthy nations have a lot of fat. They eat a lot of fat; they eat a lot of sugar; they get less exercise; they smoke more cigarettes; they drive more cars; they have more televisions.

There's a world of difference between the countries that eat low-fat diets and the countries that eat high-fat diets. And to finger fat because that's what you have in your mind to go in [to the study], is just bad science. But that's what they did, and that's how animal fat came out of it. We knew that animal fat, saturated fat, raised cholesterol, LDL cholesterol, the bad cholesterol, and it was just this sort of series of suppositions--

And we knew that cholesterol was associated--

And we knew that cholesterol was associated with heart disease. The higher the cholesterol, the higher the heart-disease risk. Although when you actually look at the studies, [it's] kind of amazing. If you or I were to reduce our cholesterol levels by 30 milligrams per deciliter, we would probably increase our chances of living an extra 2 years by one-thousandth of a percent or something. For the actual individual who doesn't have extremely high cholesterol, lowering cholesterol makes very little difference in how long you're going to live.

There were several studies done in the late '80s, where they actually calculated how much longer you would live if you cut back on saturated fat. If everyone in the country cut back on saturated fat to that recommended by the government, and cut back their total fat consumption, you could then calculate from these studies how much longer you would live. And the answer was a days to a few months. And as the authors of this study pointed out, that was published in the Journal of the American Medical Association, those are at the end of your life. It's not like you get an extra month between 46 and 47. It's, you're in the nursing home and you die at, say, 77 and three weeks instead of 77 and one week. One commentary that was published along with one of these results said this is the equivalent of rearranging the [deck] chairs on the Titanic.

So you think right off the bat something went wrong. Clearly the differences between these countries has to be environmental factors?

Yes. The idea was, when you follow immigrants from one country to another, they tend to adopt the heart disease rates and cancer rates of the country they've moved to, so that suggests that it's not genetic, it's environmental. And then the question is: What is the environmental factor?

In the '50s, '60s, and '70s, there were a school of British researchers who said it's sugar, flour, white rice, what we now call "easily digestible carbohydrates" or "high glycemic-index carbohydrates." The diet doctors pushing low-carbohydrate diets, like Atkins and Taller and people like this, were sort of disciples of these British researchers. They read some of their writing, ad the idea was, primitive peoples, when they adopt Western diets, [they] adopt Western diseases as well: diabetes, heart disease, obesity, the foremost ones; some cancers -- colon cancer and breast cancer.

These British researchers pushed this theory and it kind of got run over by the dietary fad, cholesterol, heart disease dogma. [Other] researchers said: Well, if sugar and refined carbohydrates don't raise cholesterol, then they can't cause heart disease. Or if we can't prove beyond a shadow of a doubt that every country that has a high sugar consumption has high heart disease, then that means the theory's not true.

There were two different standards at work. In the heart disease dogma, every piece of positive evidence supported the hypotheses and moved it forward, and every piece of negative evidence, contradictory evidence, was ignored. In the refined carbohydrates theory, every piece of negative evidence was proof that the theory was wrong, and every piece of positive evidence was ignored. So you had two entirely different standards. One of them moves forward to become the theory we're living by today, this idea that if we cut back on fat, we'll be healthier. And the other sort of gets squelched.

You start to see the quality of this science, the foundation, is not what you thought?

Well, the first thing I did, I wrote an article for the journal Science, where I just looked at the question of fat and heart disease. And it was fairly clear from that, that if saturated fat has any effect on our heart disease risk, it's small. Having done that, and not being enraptured by this idea that saturated fat is evil, I then actually just pitched a story to The New York Times Magazine, saying, "I want to find out what started this obesity epidemic."

The obesity epidemic starts between 1976, say, and 1986. We're fairly confident about that because there're these series of National Health Examination surveys, and we know that in the third NHANES survey, obesity rates are still 14 percent.

Up until about 1980.

Yeah. Basically, up until about 1980, the obesity rates in this country are 12 to 14 percent. And then somewhere in that period between the late '70s and late '80s, they shoot up to 22-25 percent. That's known as the obesity epidemic, and the idea is: What explains it?

From my fat research, I already knew that there were two major changes in the country during that period. One was, high-fructose corn syrup came in as sort of the primary caloric sweetener in America, which was my personal bias. I thought that it was high-fructose corn syrup because I'm allergic to high fructose corn syrup. …

The other theory was that we started pushing the low-fat diets during this period. Starting in 1977, the government started telling all Americans to eat less fat, and starting in the mid-'80s, we started producing these low-fat products that in effect replaced the fat in the yogurt or the cookies or the whatever with carbohydrates. We went from being a country that ate about 40 percent of their calories in fat and 45 percent carbohydrates, to 34 percent fat and that much more carbohydrates. Conceivably, this belief that set in, that carbohydrates could be eaten to excess and wouldn't cause weight gain, that they were both heart healthy and the ideal diet, might have had some effect on weight.

I just went off to try and find out what the answer was. I didn't know when I went in, and the more research I did, the more it became clear that this argument, this hypothesis, the alternative hypotheses that carbohydrates cause weight gain, had validity. Didn't mean it was true. Just meant that it had validity. It could be true, and if it could be true, then the way you would check is to put people on low-carbohydrate diets. You go and look at the low-carbohydrate diet idea, and lo and behold, there's Robert Atkins, who's been pushing low-carbohydrate diets for 30 years, and people swear by them. I had my former experience where I knew that at least for me, I knew it was very easy to lose weight on this diet.

I found out while I was doing my reporting that there had been five studies recently done, clinically controlled trials comparing high-fat, high-protein diets like Atkins to low-fat, low-calorie diets of the kind the American Heart Association was recommending. And in each case, the people on the Atkins diet had twice the weight loss, and their cholesterol profiles, if anything, got better than the people on the American Heart Association diet. So I felt confident saying: Here's an alternative hypotheses that has validity. Here is one set of tests from the hypotheses, that seem to confirm it. Doesn't mean it's true, but it seems to confirm it, and what now needs to be done is more studies.

So your article comes out. … What was the reaction?

Some people said it was the best article they ever read, went on the diet. I got crucified in a variety of publications. A Washington Postreporter went after me, who had been advocating low-fat diets since the early 1980's. The Center for Science in the Public Interest went after me for having the nerve to suggest that low-fat diets might not be healthy. They'd been probably the primary force in the 1970s pushing low-fat diets, and through the 1980s. It was fascinating. They go after the messenger as much as the message. ...

[Talk about the difference between diet and other topics you have covered.] Is there more ideology?

Certainly diet became a religion. The whole low-fat idea, as much as anything, came out of the counterculture and Berkeley and San Francisco in the '60s, this idea that eating fatty meat, in effect, is the dietary equivalent of conspicuous consumption. There were famines going on around the world, people were starving, and here in America we were eating eggs and bacon for breakfast and huge steaks for dinner. This was just unacceptable politically, sociologically, ideologically. It merged with this idea that fat might cause heart disease, and then blossomed in the '70s.

Many of the health reporters who cover this, many of the researchers who report on it, are vegetarians or close to vegetarians. So it becomes much more than just a subject -- I mean, people are more polarized in this than they are in politics. I've had friends who have accused me of having a brain transplant, because suddenly I turned around and said maybe low-fat diets don't work, and may low-carbohydrate diets are the answer. It's as though the data becomes irrelevant. The evidence becomes irrelevant. Everyone knows what the answer is, and it's a little frustrating even from my point of view, because no matter how much research you do, you're going after a monolithic dogma, in effect. And dogmas protect themselves.

That's what I found out when I wrote my Times piece. Everybody involved says, "We're right. We've invested our whole lives in this. We believe it." Everyone believes it, and it's hard, once it's established, to even criticize it or be skeptical without being pegged as somebody who's self-interested or somebody who doesn't care that Americans are out there dying of heart disease.

Nutritionists do admit anecdotally that Atkins works. How do they explain it away?

The first Atkins-like diets were explained away because the people who advocated them suggested they had a metabolic advantage over low-fat diets. Say you have two diets that are 1,200 calories, one's low fat, one's low carbohydrate. These people said the low-carbohydrate people will lose more weight on the same amount of calories. Researchers came along and they did studies and they said, "No, if we give both groups 1,200 calories, they're going to lose the same amount of weight." So that allowed them to say the [low-carbohydrate] diets are no different than any other diets.

Then the diets kept coming up. They kept being popular. And the next question was: Well, the people on the low-carbohydrate diets don't eat as much calories, so even though you tell one group of people, "Eat less fat and east less calories," [on] a calorie-restricted diet, and [for] the Atkins-like diet, you say, "Eat as much fat as you want, eat no carbohydrates, eat as much food as you want. So you can go out and have 10 porterhouse steaks a day, but as long as you don't eat carbohydrates, you're going to lose weight."

First the critics said this is thermodynamically impossible. Who knows? I have no idea. If you eat 10 porterhouse steaks a day, maybe you'll lose weight, maybe you won't. That's another long story.

So [low-carb advocates] said, "Okay, if people are losing weight on this diet, we're telling them to eat as much as they want but they're eating less. So why are they eating less? Why is it so easy for them to eat less?" And the answer was: Well, they're either getting nauseous, because this state of ketosis which is caused by these diets can sometimes create nausea in the beginning, or you just can't replace the calories. If you give up the carbs in the diet, you can't eat enough fat and protein to make up for it -- which is kind of ironic because since the early 1980s, we've been told that what makes us fat is not the bread but the pat of butter we put on top of it, not the baked potato but the sour cream that [we] put on top of it. It just seems that they want it both ways. On one hand they say, if we just add one pat of butter and sour cream to a baked potato, on our white bread, we're going to get fat, and it's the butter and the sour cream that do [it]; but if we only eat the sour cream and we only eat the butter, we can't replace the bread and the baked potato with enough meat or fish or cheese or whatever, to replace those calories. ...

The other response to the Atkins diet has been to say it was unhealthy.

Yeah, there're two factors. The Atkins diet, because it's very low in carbohydrates, it can be ketogenic. That's why your body, in effect, stops running on glucose, on blood sugar, and starts running on fat, and the fat's broken down into these ketone bodies. Ketosis is a mild version of diabetic ketoacidosis, which is the state that occurs in uncontrolled diabetes, and it's fatal.

This whole medical society grew up basically thinking ketosis is bad, ketoacidosis is bad, and therefore ketosis in these diets is bad and you should do anything you can to avoid these ketogenic diets. In fact, many of the compromise diets from the 1930s through the 1990s were diets that cut back carbohydrates to just the level above which you won't have ketosis.

So on one level, ketosis is bad. That was always the message, and the other level was, these diets are high in fat, and if they're high in fat, they're going to cause heart disease. One study was done by this fellow John La Rosa, who went on to be a big administrator in the American Heart Association. He did a study in 1981 where he said he put these people on a Atkins diet and their cholesterol levels skyrocketed. Their weight plummeted, and if you actually look at the study, it's almost impossible [that] what he says happened. It's really fascinating that you take somebody from the American Heart Association, you have him do a study on the Atkins diet in 1981, and the cholesterol levels skyrocket, even though the people lose like 20-30 pounds. What he said happened should not happen, even if the diet was atherogenic, as they say.

Then 20 years later, you have unbiased people do the same experiment. Lo and behold, cholesterol doesn't go up at all. [However], once [the American Heart Association] showed that cholesterol went up, that was the end of the Atkins diet. Cholesterol caused heart disease. You go on this diet, it may reduce your weight, but you're going to die of a heart attack.

One of the things I had always tried to understand, the orthodox wisdom is [to] cut back. Just eat less, and yet people eat less and they don't lose weight. I've eaten less and I've not lost weight. I mean, it doesn't seem to work, and I kept saying to myself: Why can you tell people over and over again [to] eat less, and yet they don't lose any weight? One possibility is that every time you tell them to eat less, you tell them to eat less fat as well. That's what we did in the '80s and '90s. We even stayed away from avocados and peanut butter, which we now know have good fats in them. ...

And now the consensus is that the Atkins diet is not necessarily dangerous but it's a trick.

Yeah, that's the compromise position: "Okay, it doesn't raise cholesterol. We were wrong about that." Other people said, "well, there're probably other reasons saturated fat causes heart disease." It's fascinating. There was this train of logic that said saturated fat raises LDL cholesterol and that's a risk of heart disease. Then if they come up with a diet that says saturated fat doesn't raise LDL cholesterol, then they turn around and they say: "Well, saturated fat must cause heart disease in other ways." So saturated fat, by virtue of being saturated fat, is now unhealthy. There's nothing you can do to change that. Even if you have a diet high in saturated fat that doesn't raise cholesterol, it's still a risk factor for heart disease. The logic is circular and sophistic. …

The thing they never pay attention to -- and I've interviewed probably 300 or 400 researchers in the obesity/heart disease field in the past four to five years, and in obesity in particular -- they do not consider hunger a physiological phenomenon. They will talk about hunger hormones, hunger genes ... But hunger to them has always been something that's purely psychological on some level, so they could put people on a diet.

Now, here's the thing. If you just reduce the amount of calories, you'll lose weight, even though there's not a single study that's ever shown that. But this [is] what they know for sure, so we're going to put people on a diet, we're going to tell them to eat less calories, and if they don't lose weight, that's because they didn't eat less calories. If they didn't eat less calories, that's because they don't have any willpower, and willpower's some psychological concept that you don't have but I do. I'm thin because I have willpower. And that's what it comes down to. …

When you look at the history of these Atkins-like diets, like the protein-sparing modified fast -- which is a sort of fancy name for an Atkins-like diet with a little more protein and a little less fat -- when you look at the history of these studies, even the ones that said they didn't have a metabolic advantage over low-fat diet, they all said the patients, the subjects didn't seem to be hungry. Study after study from the '40s onward. We put them on the diet, if they eat less calories, they do it because they just don't seem to be hungry. That's a physiological phenomena, and you have to be able to explain it. ...

So high-carb diets, even with less energy density, make you hungrier and therefore make you fatter.

That would be the theory. Exactly. You're hungrier. Insulin actually used to be known as a hunger hormone up until about the '60s; the idea being, diabetics are hungry to begin with because they don't have the insulin to push the blood sugar and the fat into the cells, so their cells don't see it. There used to be a treatment for anorexics. You would just inject them with insulin and they get hungry and eat. The question was: Does this cause some kind of hypoglycemia, very low blood sugar? Is that how it works? Or does it work in some other way? It was always assumed that it works by just causing very low blood sugar, which in effect causes a state called hypoglycemia, and you get nauseous and dizzy and tired, and you have to eat.

But [now] everyone agrees that insulin is the hormone that controls the deposition of sugar and carbohydrates and fat in your body. They agree that if insulin levels are high, you'll preferentially store calories as fat; and that as long as insulin levels stay high, you won't be able to get to that fat to use it for fuel. They agree that carbohydrates will raise insulin levels more than -- fat doesn't have an effect on insulin, although if you force-feed enough calories, you can [raise] it. All of that is given.

What they don't agree is that somehow the carbohydrates, the actual macronutrient content of the diet, will do this. [Scientists] will say a calorie is a calorie is a calorie. They'll admit that a calorie of carbohydrates has an entirely different effect on your hormonal system than a calorie of fats. They'll admit that your hormones can control your weight; that insulin and estrogen have effects on weight, hunger, and body weight regulation. But they will never go from the step where they say: Hey, maybe the amount of carbohydrates and the kind of carbohydrates in the diet will have an effect -- through their effect on insulin, through insulin's effect on the deposition of calories, through that effect on hunger -- [on] being a functional diet.

To me, it's almost mystifying, because I've interviewed people who have done research on each step of the way. And then I say, "This should be the null hypotheses. You should assume carbohydrates cause weight gain until proven otherwise, not the other way around. Why don't you believe that?" And they'll say, "Well, because my rats get fat on fat." And it's true. Rats will get fat on dietary fat, fatter than they will on carbohydrates. So then the question becomes: Are rats a good animal model for human obesity?

So this theory would explain a big part of the rise of obesity on the high-carb diets?

This theory would explain a big part of the rise of obesity on the high-carbohydrate diet. Yes. Basically it says: The things that are making us fat -- sugars, high-fructose corn syrup, these kinds of easily digestible sweets, flour -- some people may get fat even if they eat vegetables. I really don't know because they've never done the research. Because they've been so convinced that somehow the type of calorie is irrelevant, I'm not sure this is still an open question. But the theory would explain why we started putting on weight just when we started thinking "if we would just reduce the amount of fat in the diet, that'll make the difference."

It's not just the calories. That's the point. It's the effect of the calories on the hormones, and the effect of the hormones on how your body decides to use the calories you're eating -- is it going to burn them as fuel or store them as fat -- and that effect on hunger.

But clearly the quantity of calories has to be going up. You're saying the mechanism for that is that the carbs make us hungrier?

The quantity of calories appears to be going up. Whether we would get fat anyway -- we've all had this experience where our weight fluctuates, apparently independent of how much we seem to be eating. If you chronically change your insulin levels, you will change your weight by doing it. So the question is: Can you do that by increasing calories, or do you do that simply by increasing carbohydrates and keeping the calories constant? Good research in the '80s by established researchers showed you can do that just by changing the amount of carbohydrates. ...

Does your story have big holes in it too? Every time you try and reduce things to single macronutrients, you run into--

No, actually, you look back to one of the things that prompted the whole dietary fat and heart disease theory was the reduction in heart disease rates in occupied Europe during World War II -- and diabetes rates and cavities, I might add -- they plummeted. People said they're eating less cholesterol. Then that was knocked down. Then they said they were eating less fat, and that was the theory.

Out of these studies that came out of occupied Europe, that was what generated one of the major legs of the theory that fat -- it's a tricky question because you can also argue that doctors in occupied cities in Europe and Scandinavia might not be making the effort to diagnose heart disease and diabetes as they were during the war, or before the war or after. The evidence that something dramatically changed the incidence of disease during the war years is pretty compelling. It could have just been less calories. We're now fairly confident that if you cut back on calories, you'll cut back on disease rates, and not just heart disease but cancer. But the question is: Then what makes you cut back on calories? And now you're back to, you know, Ancel Keys tried to get his conscientious objectors to cut back on calories. So now you're back to what causes hunger. And it takes back into this same hypotheses.

Most researchers now would say that calories are probably the most important factor, calories and weight, so you're still left with: What is it that makes you eat more calories?

What would be your prescription for curbing the obesity epidemic?

There's compelling evidence that low-carbohydrate diets work. Clinical trials suggest they work, [as does] anecdotal evidence for 150 years. People, when they wanted to lose weight, gave up sugar, gave up starch and we all grew up believing this, even into the '70s. Jane Brody, theNew York Times health reporter, writes a bestselling book in 1985 where she tells everyone to go out and eat starches to their hearts' content, but first she says we all grew up believing that what causes obesity is bread, rice, pasta, potatoes, sugar.

It's fascinating. For 150 years since Jean Anthelme Brillat-Savarin in 1825 writes The Physiology of Taste and says, "I know what cause obesity. Just talk to fat people. They eat too much starches and sugars." He says this. "I have 500 conversations over the year with stout people, and each one, they're telling me, 'I love the potatoes. I love the rice. I love the bread.'" Since then, it's sort of been institutionalized that carbohydrates -- starches and sugars -- make you fat.

The '70s come around. We decide that fat gives you heart disease. We have to eat low-fat diets, low-fat diets heavy in starches and sugars, and we start getting fatter. ...

You're not talking about a diet with no carbs, just a reduced amount?

The underlying philosophy is this kind of Paleolithic diet theory. It's what we ate during the 2 million years that we were hunter-gatherers on this planet. The fact that we were hunter-gatherers for 2 million years suggests it was an extraordinarily successful evolutionary adaptation. The question is: What did we eat during these 2 million [years] when we left the jungle, the trees, went down into savanna and started surviving on whatever we could hunt or gather? That's the philosophy. The answer is, probably considerable meat, very low glycemic index, hard-to-digest roots and starches, and fruits and berries that look nothing at all like the beautiful Fuji applies you can buy at your local market now. Some carbohydrates, but whatever it was, it wasn't refined. It wasn't sugar. It wasn't flour. It wasn't easy to digest. That's my going theory. If this theory's right, the diet we evolved to eat is probably the correct diet.

Just as [with the] low-fat fad, when manufacturers took fat out and put carbs in, and people ate a lot of low-fat ice cream because they thought it was not fattening, and they got fat, might not the same thing happen if you produce low-carb products?

It's conceivable. The idea that it's what we evolved to eat, we never evolved to eat refined protein either, which is basically what they're giving us. I have no idea what those foods will do in the long run. I mean, I've actually tried quite a few myself, and they don't seem to affect weight in any way. They do seem to keep insulin levels down, if that's what's actually happening. ...

Unlike Walter Willett, who says some fats are good but others are bad, you'd say a quarter house steak would be a perfectly decent meal?

Let's put it this way. When you look at the historical record and the literature, you find plenty of reasons to blame the refined carbohydrates on the chronic diseases that affect us, and it's hard to come to a point where you can finger saturated fat as actually being meaningful. There's this interesting theory, originally pushed by a fellow named Crawford, who was a researcher in Kenya in the '60s. It's this idea that the grazing animals eat a much wider variety of fats and carbohydrates. They have much great sort of tapestry of fats in their body, and they have much more unsaturated fats than saturated fats, and therefore that constitutes a healthy meal. That's a shift in the spectrum of fats we're eating, not the introduction of an entirely new type of food, like refined carbohydrates.

The question is: Can that shift in the spectrum from more unsaturated fats to more saturated fats really be that important, after you've removed this dramatic shift of no refined carbohydrates to refined carbohydrates? I don't know, and Walter doesn't know either. He's just telling you that he believes it's the case. ...

The other theory has to do with activity. We're an increasingly sedentary society.

One of the problems with that theory is that the highest obesity rates in this country are in the poorest members of the population. [Those scientists] have to explain, for instance, why it is that those individuals who are most likely to do manual labor are the ones who are most likely to be obese. Hispanics, for instance, come to America, they get high obesity levels here, and they're not coming here and taking white-collar jobs. You have to be able to explain that before you can say it's obesity.

You have to be able to explain why it is they've never been able to show that if you exercise more, you'll actually lose weight. When you read the research articles from the '70s and '80s and '90s, they're fascinating. They'll always start with a introduction that says exercise and physical activity is crucial to weight loss and weight maintenance. Then they'll move into the main part of the paper, where they'll go through study after study after study, where they acknowledge that these studies fail to show that you could actually lose significant weight by exercising or being more active. Then they'll get to the conclusion, and they'll give you a half a dozen techniques by which you can then make exercise part of an important weight loss or weight maintenance program. It's surreal reading these things. The book ended [with] the advice that you have to exercise, but the actual studies show that doesn't do any good.

They say the people who control their weight the best tend to be more wealthy, better educated. What are they doing right?

First of all, they say that the same people also experience an obesity epidemic. Their absolute levels of obesity are lower than the lower classes, but the amount that obesity increased was the same. Among poor, rich, it didn't matter. They all went up like 7 percent during this 10-year period of time.

Second thing is, carbohydrates are the cheapest calories. So the poorer you are, the greater the amount of carbohydrates in the diet. You go back and you read the obesity textbooks and the obesity monographs in the '60s and '70s, and people have to explain why there's so much obesity among poor people, and they invariably say, "Well, that's because they eat so much fattening starches." You had this concept once again of fattening starches. ...

What do you hope to achieve, writing your book? You're making a case that there's a lot of bad science, food ideology. Are the vested interests too powerful to change?

It's interesting. In my wildest fantasies, people are sort of liberated from this belief that they have to reduce the fat in their diet, and they try it. If they're overweight and they want to lose weight, they try going back to the old-fashioned way of giving up sugars and starches and seeing what happens. In writing the book, I want to explain what to me is a fascinating episode in science sort of gone awry, and in the same time write about some fascinating science that's simply been ignored, some beautiful, elegant studies that people have paid no attention to, and maybe show some people not just how body weight regulation works in the human body, why we gain weight, why we lose it, and what to do, but also explain how science works and how it doesn't work, and when it is successful and when it fails, and what's good science and what's bad science. That's what I've been writing about in my whole career.












Indulge me just for a minute. I want to start on a personal note here. It's the beginning of the new year. I'm about to be 55. So far, so good. I now weigh between 205 and 210 pounds, and I'm just shy of 5'11." So when I look up on these body mass index charts, I see that I am 28-29, which is shocking to me, but that's considered high overweight. … They say obesity -- a word I don't like to hear -- starts at 30. So I'm in the high overweight category. And in your book, the ideal weight chart for me would be about 180 pounds. So what should I do?

You know, there's no mystery in how you lose weight. It's: You burn more calories or you eat fewer calories. You can burn more calories by exercise, for example, which is why any kind of exercise can help you lose weight. And you can eat fewer calories in one of two ways. One is, you can just eat less food, which is why you can lose weight on any diet if you eat less of whatever it is, because if you eat less food, then you're going to eat fewer calories. The problem is, you get hungry, and sooner or later, most people get tired of feeling hungry and deprived, they get off the diet, they gain the weight back, and then they usually blame themselves for not having enough discipline or willpower or motivation, when the real problem was that they were just going about it in the wrong way.

An easier way to eat fewer calories is not just to change the amount of food but the type of food, because fat has 9 calories per gram, whereas protein and carbs only have 4. So when you eat less fat, you eat fewer calories without having to eat less food. And so you can enjoy what you're eating, and you can eat whenever you're hungry, you can eat until you're full, but you lose weight and you keep it off without hunger and without deprivation. Because even if you eat about the same amount of food, if you eat a low-enough-fat diet, you're getting about a third fewer calories, as opposed to eating a third less food. So this is a diet that people can sustain. I wrote a book called Eat More, Weigh Less, which is really based on this concept.

I've actually picked this book up. It's in all the bookstands. But Eat More, Weigh Less? I mean, that's a fairly provocative title. Is that possible, really?

… A study from the National Institutes of Health found that most people who lose weight, two-thirds of the people who lose weight, gain it all back within the first year, and 97 percent gained it back within five years. We looked at the data from our studies and we found that people were able to lose weight and to keep it off without hunger and without deprivation, because they changed the type of food and not just the amount of food.


Dr. Dean Ornish is a cardiologist and the author of Eat More, Weigh Less. He is a strong advocate of a low-fat diet and suggests that high-protein, low-carbohydrate diets, such as Atkins, are based on "half-truths." "If you're eating a typical American diet, which is high in simple carbs, and you go on an Atkins-type diet, you may lose weight because you're eating fewer simple carbs," he says. "But you could lose even more weight by eating fewer simple carbs and less fat, because both are the reasons why people get too many calories." Ornish says his diet has been proven to stop or reduce heart disease and has been backed up by scientific studies. "The burden of proof is on people who promote-high protein diets," he tells FRONTLINE. This interview was conducted on Jan. 2, 2004.



… Your studies show that with your diet, with a low-fat diet, you can really lose weight and keep it off?

Yes. We found the average person lost 25 pounds in the first year. They kept half that weight off five years later, and we weren't even trying to get them to lose weight. This was a study to reverse heart disease, which we were also able to show for the first time. And we published this in the Journal of the American Medical Association, The Lancet, and other leading peer-reviewed journals. And so what sets this program apart from most of the other weight-loss programs is that it's been scientifically proven and it works, and the reason it works is because it's based on abundance rather than on deprivation. You can eat whenever you're hungry, you can eat until you're full, and you can still lose weight and keep it off. …

One of the reasons I wrote a book called Eat More, Weigh Less -- and it was designed to have a provocative title, because if I called it, you know, How to Help Prevent Heart Disease and Cancer and Lots of Bad Things, it wouldn't have been as interesting to people. In a way, you really can lose weight and keep it off by eating this way, but you're also enhancing your health at the same time, because we've done studies that you can actually reverse heart disease and may be able to stop the progression or even reverse some of the more common forms of cancer, like prostate cancer.

But what concerns me about the high-protein diet books, like the Atkins book, is that it's the opposite. There are ways of trying to get people to eat this way to lose weight, but they may be mortgaging their health in the process rather than enhancing it.

How so? I mean, reading your book, you really say that the Atkins diet and diets like it are dangerous to your health. How dangerous?

Well, I think they are dangerous to your health, because there's a wide body of evidence from scientific studies showing that when you go on a high protein diet, you significantly increase your risk of heart disease, diabetes, hypertension, breast/prostate/colon cancer, most of the chronic degenerative diseases. [In] the studies that have been done on the Atkins diet, none of them have actually looked at underlying diseases. They've only looked at what are called risk factors, like cholesterol and triglycerides and HDL.

In our studies, ironically, we use the latest high-tech, state-of-the-art measure to prove how powerful these very simple and low-tech and low-cost interventions like diet can be. And we weren't looking at risk factors. We were looking at actual underlying disease, and what did we find? We found that even people with severe heart disease, that 99 percent of them were able to stop or reverse the progression of their heart disease. We found there was a 91 percent reduction in the amount of chest pain or angina, and that occurred within the first few weeks. What that means in real life terms is that people who literally couldn't walk across the street before the light changed without getting severe chest pain, they couldn't walk, they couldn't have sex, they couldn't take a shower, shave, or just do the normal activities of daily life, within a few weeks were essentially pain-free, without bypass surgery or angioplasty or changing their medications -- except in most cases, under their doctors' supervision, to reduce or even get off many of these medications.

So having seen what a powerful difference these changes in diet and lifestyle can give people, it saddens me that so many people are being misled by this idea that by telling people what they want to hear, that somehow that they think that bacon and eggs are a health food, and they're not. I think people need to know that.

Why are the Atkins diet and diets like it so incredibly popular? And also, why do they seem to work?

They're popular because they tell people what they want to hear, and they work to some degree because they're based on a half-truth. I debated Dr. Atkins many times before he died, and so I'm very familiar with the Atkins diet. The half-truth is that Americans eat too many calories. One reason is that they eat too much fat, because fat is so dense in calories. The other is that they eat too many simple carbohydrates, and that's the area that we both agreed on.

The problem with simple carbohydrates -- and these are things like sugar, white flour, white rice, alcohol, which your body converts to sugar -- is that you get a double whammy. You get all these calories that don't fill you up, because when you go from, say, whole wheat flour, which is complex, to white flour, which is a simple carbohydrate, you've removed the fiber and the bran. Those ordinarily would fill you up before you get too many calories. You can only eat so many apples. You're going to get full before you get too many calories. But when you remove the fiber and the bran, you can consume virtually unlimited amounts of, say, sugar or white rice without getting full.

So, basically all agree that white rice, white bread, things like that, lay off. Alcohol. All these diet plans, essentially.

If you're trying to lose weight, it's better to avoid or reduce the intake of simple carbohydrates. We agree on that.

The other reason that simple carbohydrates cause people to gain weight, besides the fact that you can eat so many without getting full, is that they get absorbed quickly. So your blood sugar zooms up, your pancreas makes insulin to lower your blood sugar, which is good, but insulin also causes you to convert calories into fat, which is not good. We both, Dr. Atkins and I, agreed that Americans eat way too many simple carbs, and so if you're eating a typical American diet, which is high in simple carbs, and you go on an Atkins-type diet, you may lose weight because you're eating fewer simple carbs.

But you could lose even more weight by eating fewer simple carbs and less fat, because both are the reasons why people get too many calories, and rather than harming your health, you'd be enhancing it by eating the way that I suggest. Because it's not only what you exclude in your diet; it's what you include that's protective. A number of studies have shown that there are substances that have anti-cancer, anti-heart disease, anti-aging properties: things like phytochemicals and bioflavonoids, carotenoids, retinals, isoflavones. There's a whole alphabet soup of these. Where do you find these protective substances? With few exceptions, you find them in fruits, vegetables, whole grains, and soy products and other legumes. To tell people they shouldn't be eating these foods saddens me.

I'd love to be able to tell people that bacon and eggs are health foods, but they're not. A number of studies have shown that eating a diet that's rich in animal protein increases your risk of osteoporosis, kidney disease, and heart disease, and the most common forms of cancer, particularly breast cancer, prostate cancer, and colon cancer, and lymphoma. …

When I read some of what you've written, you don't care for meat.

I grew up in Texas, eating meat five times a day, and I liked meat. But I began being a vegetarian when I was 19 because I found that I felt better. To me, there's no point in giving up something that I enjoy unless I get something back that's better, and quickly. Studies have shown now that your brain gets more blood; you think more clearly; you have more energy; your heart gets more blood in ways that we've measured; your arteries get less clogged in ways that we've proven. Even your sexual organs get more blood flow, in the same way that Viagra works, and so for many people, these are choices worth making.

Now, you don't have to be a vegetarian if you're just trying to lose weight and be a little healthier. There's a whole spectrum of choices, but to the degree that you move in that direction, you're going to lose weight and gain health.

You're saying the Atkins diet people -- their breath is bad, halitosis, constipation, headaches, hair loss?

I'm not saying this. This was actually in the study in the American Journal of Medicine by Dr. Eric Westman from Duke, that was actually funded by the Atkins Center as one of the first studies that came out on the Atkins diet, and that's what they found. The reason is, that's how your body gets rid of toxic substances, toxic waste, is through your breath, your bowels, and your perspiration. So if you go on an Atkins-type diet, you might start to lose weight and start to attract people towards you, but when they get too close, they might have a problem because of the way that you smell.

It doesn't sound so good.

It's not so good. And even more worrisome are the studies that actually look at blood flow to the heart. There was a study that Dr. Richard Fleming did in Omaha, that was published in a peer-reviewed journal, where he put people on a diet, one like I would recommend, or on an Atkins-type diet. And on the diet like I would recommend, the blood flow to the heart improved. They replicated what we found. But on the Atkins-type diet, the blood flow to the heart actually worsened, and that is really what concerns me, is that studies have come out saying: Well, you know, the Atkins diet is better than, you know, a so-called low-fat diet because your HDL goes up on an Atkins diet and your triglycerides may go down.

Meaning what?

Meaning that -- the HDL is the so-called good cholesterol, and people think that anything that raises your HDL is good and anything that lowers it is bad. But again, that's a half-truth as well, because your body makes HDL -- think of it like garbage trucks. So if everybody's eating the same kind of diet, like a typical American diet, those people who can make more garbage trucks, make more HDL, are going to be at lower risk than those who can't. They've got more garbage trucks to take out the garbage, so they're going to be healthier.

That's very different than: if you put people on a really healthy diet, like what I recommend, we've found that their HDL levels -- the so-called good cholesterol -- may actually go down a little. The bad cholesterol goes down way more. But the point is that in these same patients we found their arteries became less clogged, the blood flow to the heart improved. They got better. It's almost like your body says: Hey, there's not as much garbage; I don't need as many garbage trucks. And so it has a very different prognostic significance to have a lower HDL on a healthy diet than on a harmful one. If I give you a stick of butter, your body will try to make more HDL to get rid of it, but that doesn't mean butter's good for your heart.

So are you actually saying that the Atkins diet is harmful to your health?

I think for many people it is definitely harmful to their health. And it's not just me that's saying that.

And in what way? What's the worst thing that can happen?

The worst thing that can happen is sudden cardiac death. … But even short of that, as I mentioned, the blood flow to the heart is reduced. Your kidney function may be compromised. Osteoporosis is increased. And so again, the goal is not just to lose weight.

Now, are we seeing these things? I mean, correct me if I'm wrong, the Atkins diet has been around since the early 1970s. So presumably a lot of people have done this. I walk into bookstores, I see Atkins diet books everywhere.

These are not things that I'm suggesting might happen. These are things that have been published in peer-reviewed journals, proving that they happen. Okay. This is not my speculation. This is scientific fact. And the burden of proof is on people who promote high-protein diets. When I debated Dr. Atkins, he would say things like, "Well, my diet can reverse heart disease." And I'd say, "Well, show me any data to support that." And there are none.

Whereas what we have are data published in peer-reviewed journals in the last 25 years, proving that this kind of approach can actually reverse heart disease. I think before making statements like that, the whole point of science is to help people sort out these kind of conflicting claims, and we have done the science and they haven't. I think it's incumbent upon them to do so before making these kinds of promises to people that can't be fulfilled.

Let's talk about your diet now. … The knock on the low-fat diet is that in this long stretch of time while it's been popular, in fact, Americans are getting fatter. We're in a national obesity crisis. So some people would say -- in fact some people have argued -- that the low-fat diet, the popularity of it, has in fact led to this obesity epidemic.

Well, that's silly, for one thing, and it's also based again on a half-truth. And a half-truth is that people say things like, "Well, Americans have been told to eat less fat, the percentage of calories from fat is going down, Americans are fatter than ever, therefore fat is not the problem." Actually, Americans are eating more fat than ever, but they're eating even more simple carbs. So the relative percentage of fat in the diet may be lower, but the actual amount of fat is higher than ever. The goal is to eat less fat and fewer simple carbs, and then you can do so in a way that enhances your health rather than one that may harm it.

What's your best guess as to what has caused this obesity crisis which everyone's very concerned about now? I mean, you're having fat kids and type 2 diabetes, which used to be adult onset diabetes, now people are seeing it in adolescence. It's scary.

Yeah. Diabetes in adolescence has risen 70 percent in the last 10 years. There really is clearly an obesity crisis, but it's silly to just blame low-fat diets as the cause, because they're not. They're part of the solution. The problem is that people get in good-bad ways of thinking: that all fat is good, all fat is bad; all carbs are good, all carbs is bad, when in fact there are good carbs and bad carbs, there's good fat and bad fat, and there's good protein and bad protein. And so an optimal diet is one that's high in the good ones and low in the bad ones.

So let's take fat, for example. In the early '70s and '80s, a number of manufacturers said: Oh, we'll make low-fat foods, but they're very high in sugar: The Snackwell cookies, the Entenmann's cakes and pies and so on. I even had a patient once who was starting to gain weight on a so-called low-fat diet, and I said, "What are you eating?" They said, "Oh, I'm eating just one or two a day." I said, "One or two pieces of these Entenmann's cakes?" "No, one or two cakes at a sitting." They said, "Well, it's low fat. Why not? It can't be bad for me." But it was high in sugar.

But isn't that just the problem? That someone like myself goes into a store or supermarket, and I see something that says "low fat." I think, "Well, of course. I'm going to buy the low-fat whatever it is." But then you think, okay, it means there's no fat in it, and you end up eating a lot of it.

And now the pendulum is going the other way. We're seeing, if it says "low-carb," it must be good for you. So you can buy low-carb vodka, you know, or low-carb whatever.

What people need to understand is that you want to find foods that are low in fat but also low in simple carbs, but not low in total carbs. Low in simple carbs, high in complex carbs. Fruits, vegetables, whole grains, legumes, soy products are good for you. Okay. Low in animal protein, higher in the plant-based protein. It's a spectrum. It's not "all or nothing." And to the degree that you move in that direction, you're going to feel better, you're going to look better, and you're going to lose weight.

So it's still a good thing that there are these low-fat indicators on products in the market?

I think again people need to be more mindful of what they're buying, and to read the labels. Just because something is low fat, or for that matter low carb, doesn't mean it's healthful. You want to find foods that are low in simple carbs -- the bad carbs -- [and] high in the good carbs -- fruits, vegetables, whole grains, legumes, soy products, things like that. You get a double benefit. You're reducing your intake of disease-promoting substances like cholesterol, saturated fat, oxidants, simple carbs and you're getting at least a thousand others that are actually protective.

People are making the same mistake that was made 15, 20 years ago, with thinking that all fat is bad, to think that all carbs are bad, and that's not true. Some fat is good, some is not good. The omega-3 fatty acids, for example, can reduce sudden cardiac death by 50 to 80 percent. My mentor when I was doing my training at Mass. General, Dr. Alexander Leaf, discovered this 20 years ago. Just 3 grams a day of fish oil or flaxseed oil can reduce sudden cardiac death by 50 to 80 percent and lower your triglycerides, [it] can reduce inflammation of arthritis, many other benefits. But you don't need more than that. Just a little can provide what you need without getting too much, so you can get the benefits without getting too many calories. …

Doesn't this basically come down to common sense and moderation? I mean, I know moderation doesn't necessarily sell books, doesn't sell diet plans. But isn't really the best advice to eat good food moderately and exercise?

Not necessarily. It depends on what your goals are. For example, let's say you had heart disease and you wanted to reverse it. Now, the National Cholesterol Education Program, the American Heart Association and others say: Eat a moderate diet, a 30 percent fat diet that's less red meat, more fish and chicken -- take the skin off the chicken -- four eggs a week. The problem is that that diet doesn't reverse heart disease, and it doesn't do much for your cholesterol level, and so if you came to most doctors or most dieticians, they would say, "Your cholesterol's too high. See, we need to put you on an American Heart Association diet." You come back a month or two later, it hasn't come down very much, and they say, "Gee, I'm sorry, you've failed diet. Now we have to put you on cholesterol-lowering drugs for the rest of your life," which $13 billion were spent on, just in the U.S. alone last year.

Now, what I would say is: Fine. We can try a moderate diet, and if that's enough to get your cholesterol level down, great. For most people, it isn't. … On the other hand, what we've found in our studies is that if you were to make bigger changes in diet and lifestyle, we found an average 40 percent reduction in LDL, comparable to what you can get with drugs, without the cost or the side effects of those drugs. And rather than the arteries getting more and more clogged over time, which was thought to be the so-called natural history of heart disease, we found they could get less and less clogged, that you could get better and better instead of worse and worse. And that was the first time that had ever been shown, because until then the recommendations didn't go far enough.

So if you're just trying to lose a few pounds and your cholesterol level's fine, moderate changes are fine. But if you're trying to do something more than that, if you want to get your cholesterol down more, if you want to lose more weight, if you want to reverse heart disease and perhaps some forms of cancer, you have to make bigger changes.

Now, to what degree people want to make those changes is a very personal choice. I never tell people what to do, because I learned, even more than being healthy, people want to feel free. And as soon as I say, "Don't eat this and don't do that," they immediately want to do that. That goes all the way back to the first dietary intervention, you know, when God said, "Don't eat the apple," and that didn't work. And that was God talking, so we're not going to do better than that. I used to, when I started doing this work 25 years ago, say, "Don't eat this. Do this." And that didn't work, but what does work is giving people information and say, "Look, it's your life. I'm only here to provide you the latest information so you can make informed and intelligent choices. And I'll support whatever you choose." …

Can people really stick to your diet? I mean, again, the idea that you go in, you have the conviction: I'm going to lose some weight, but you know, I'm not getting to eat the things I really like, and this isn't filling me up, and what can I do?

You know, the thing I get so frustrated by is that people say, "Nobody could follow your diet." First, the idea when I began doing studies was that heart disease can't be reversed. It's impossible. Then we proved it could be, and they said, "Well, okay. But you know, you live in California. It's an altered state. They'll do anything there. You can get people to change and no one else can. So what good is it?"

So beginning in 1993, through our nonprofit Preventive Medicine Research Institute, we began training hospitals around the country, and these were very diverse hospitals in Omaha and Des Moines and Columbia, South Carolina, where they told me, "Gravy's a beverage. This will be a big change in our diet." But also at Harvard and at Beth Israel, New York, and at UCSF and at Scripps and at Broward General Hospital. We did this and Mutual of Omaha funded it. We found that almost 80 percent of the people who were told they needed to have a bypass or angioplasty were able to follow the program well enough that they didn't need that. Mutual of Omaha saved almost $30,000 per patient, immediately, because it's so much cheaper to teach people how to change their diet and lifestyle than to operate on them. …

Now, on the other end of the spectrum, the idea that taking a pill like a cholesterol-lowering drug, like a statin drug -- Lipitor, Zocor -- is easy and everybody will do it, but changing diet and lifestyle is impossible and no one will do it, is not what the data show. Because the data actually showed that within a year, two-thirds of the people who've been prescribed statin drugs are not taking them, just a year later.

Why?

The reason is that they don't make you feel better. … If that were the choice between leading a fun, interesting life that you're going to get sick and die sooner, or am I going to live longer [or] is it just going to seem longer because life is so boring, I would choose the, you know, have fun and die sooner.

But that isn't the choice, because whereas taking a pill like a statin drug doesn't make you feel better, the paradox is that sometimes it's actually easier to make big changes than small ones. The conventional wisdom is that small, gradual changes are easy, and big, rapid changes are impossible. And I think there are people that both appeal to them. On the one end, you have the programs like America on the Move, which are really small incremental changes: Walk 5,000 steps more a day. Eat 500 or 1,000 calories less a day. That will help to prevent you from gaining weight. Anybody can do that.

But it's also true that when you make really big changes, most people find they feel so much better so quickly, it reframes the reason for making those changes from fear of dying to joy of living. Because your brain gets more blood. You think more clearly. You have more energy. …

But if you don't want to make big changes, make small changes. You have a spectrum of choices, and the nice concept about a spectrum is that it preserves the feeling of being in control. You're free. If it's a diet you get on, it's a diet you may get off. You feel constrained immediately when you get on a diet. "Oh, I can't eat this, I can't eat that." Instead if you say, "Look, I'm going to try to eat more on the healthier end of the spectrum. More fruits and vegetables, more whole grains, more soy products, less red meat, less simple carbs, you know, fewer of the bad stuff, more of the good stuff. If I want to go out and indulge myself sometimes," and [if] you don't have a heart problem, it's no big deal. "Maybe I'll just eat a little healthier the next day to make up for it."

Some studies have shown that the healthiest people are those who actually indulge themselves from time to time, but that allows them to eat healthier the rest of the time. By having it as a spectrum of choices, it's a way of living, it's a way of eating. It's not a diet that you get on and get off. And otherwise, if you get off the diet and you eat something you're not supposed to eat, you feel like, "Oh God, I'm a loser. I failed." And that makes you feel depressed, which makes you want to eat more, and it just becomes a vicious cycle.

I want to ask you about exercise, because the old clichÈ [is], "no pain, no gain." You got to go in and suffer. And you say no, moderate exercise is better. …

Right. Well, fitness and health are not the same thing. The more you exercise, the more fit you become. That's it. Now, what gets people into trouble is when they are weekend warriors, when you don't do anything six days a week and then you go out and play full court basketball or shovel snow. That's not a good idea, and those are the people who drop dead. If you're going to exercise more than just walking, that's great, but do it on a consistent basis. If you can't do it consistently, it's better just to do something more lightweight like walking.

Now, what's also interesting is that studies have shown that from a health standpoint, walking 20 or 30 minutes a day can cut premature death rates in half. These are studies that Ken Cooper and Steve Blair and others did, who were very big exercise enthusiasts, and that's really not what they expected to find. They thought the marathon runners would do better than the people who ran, jogged, and they'd do better than the walkers, and they'd do better and so on. But they actually found that if they were looking at different levels of fitness, the sedentary people had the highest death rates; the people who walked 20 or 30 minutes a day were cut in half, and there was just a slight improvement beyond that for doing more than that. …

There was a New York Times magazine article, got a lot of press … "What If It's All Been a Big Fat Lie?" Gary Taubes attacks what he calls the low-fat dogma, and says that diets like yours have led Americans to be fatter, that you're part of the problem.

The reason I spend so much of my time doing science is that the whole point of science is to help people resolve conflicting claims by saying: Show me the data. Now, we've spent 25 years conducting randomized control clinical trials, published in the leading peer-reviewed journals, like the Journal of the AMA, The Lancet, Circulation, New England Journal of Medicine, and so on. And what did we find? That when people eat this way, they lose weight and keep it off. Those who have heart disease were able to reverse it, and we were the first to be able to prove that. And more recently we're showing that even the progression of some of the most common forms of cancer, like prostate cancer, may be improved when people go on these kinds of diets. LDL cholesterol, the bad cholesterol, went down by an average of 40 percent.

Now, when someone like Gary Taubes, who's not a physician, writes an article attacking, I say, "Show me the data." Now, the data that he talks about are purely circumstantial. He'll say things like, "Well, Americans have been told to eat less fat. The percentage of calories from fat is down, and yet Americans are fatter than ever. Therefore fat doesn't make you fat." Now, he knows better, because I've actually debated him as well. And it's a half-truth. The percentage of calories from fat is down, but actually Americans are eating more fat than ever. The only reason that the percentage is lower is that they're eating more fat and even more simple carbs. So the goal is not to say, fat is good, carbs or bad, but to say there are good fats and bad fats, there are good carbs and bad carbs, there's good protein and bad protein, and so an optimal diet would be low in the bad carbs but high in good carbs. …

So something like this article, "A Big Fat Lie," this is just balderdash? This is provocative? This is selling newspapers?

Well, it is provocative. It does sell newspapers. And you know, it tells people what they want to hear, which is also a good way to sell newspapers. It's like that scene in Woody Allen's movie Sleeper, where he wakes up a few hundred years in the future and finds out that chocolate and steak are good for you. …

[There's a] big debate over revising the food pyramid. Walter Willett at Harvard [has suggested a revised food pyramid]. What do you think of his work?

Well, I'm a big admirer of Walter Willett's work. I think he's done some really important research. He and I agree on most things. We both testified before the U.S. Senate recently about the need to change the food pyramid, and the reason is that a lot of decisions get made based on the food pyramid. It's not that most Americans, you know, spend their time looking at the food pyramid, but a lot of food service people and schools and others do. And so to that extent we agree.

The only area we differ on is that he's a big proponent of olive oil. Olive oil is a better choice than, say, butter, but that's different than saying that it's really good for you. The concerns I have about olive oil are that olive oil, like any oil, is pure fat. One tablespoon of any oil has 14 grams of fat. So people who pour olive oil on their salad, or they dip their bread in it, get tons of calories that don't really fill them up. If they just were to reduce their intake of oil, they'd be better off. …

You've been at this for a long time, and you came to it as a way to deal with heart disease. When you read the statistics about obesity, when you look at size or portions of food that are being served, do you think of this as a losing battle? I mean, do you ever give up hope? It's kind of depressing, isn't it?

I never give up hope. I wouldn't be doing this work if I felt otherwise. … You can get depressed when you look at the statistics, but at the same time heart disease rates have actually been declining substantially in the last 30 years, I think in part because of people changing their diet. Americans, unfortunately, are eating more fat than ever. It's not that they're eating less fat. They're eating more fat, so I think that we need to get the information out to people who can benefit from that.

I used to think if I just did good science that would change medical practice. In retrospect, I think good science is important but not sufficient. We also have to change reimbursement, which is why I've been working with insurance companies and now Medicare. We doctors do what we get reimbursed to do, and we get trained to do what we get reimbursed to do. If we change reimbursement, we change not only medical practice but even medical education. So we can start to get nutrition into schools, which are so lacking in such a terribly important area that affects everyone.

I've been working with some of the major food companies and consulting with them, like PepsiCo and McDonald's and others, and ConAgra, to get them to make healthier foods, and to use the wonderful resources and advertising and celebrities and so on, to make it hip and cool and fun and exciting to eat healthfully, to make it convenient, to make it tasty, to have healthy foods in vending machines and so on. And then I think we can make a difference by taking a coordinated approach.

On the other hand, when people say thing like, "Oh, fat's okay, you can eat all you want," I think that's a real disservice, and it makes me sad because I think it's going to push people in the wrong direction. …

Why then, [is] the Atkins diet so popular now?

Because it tells people what they want to hear. You know, it tells people that bacon and sausage and pork rinds and butter and brie are good for you. And nothing could be further from the truth.

Brie is not good for me? [laughs] You're killing me here, Dr. Ornish.

Now, the other thing that we really haven't talked about are the studies that came out like in the New England Journal of Medicine, saying the Atkins diet is good for you. Now, I have two problems with that. First of all, what are they comparing to? They're comparing it to an American Heart Association's 30 percent fat diet, which I've been critical of for years. And so what they found is that the LDL cholesterol on both diets actually went up, the bad cholesterol went up, but the triglycerides went down more on the Atkins diet, and the HDL went up more on the Atkins diet.

Now, the triglycerides went down because the American Heart Association diet is very high in simple carbs, which I've been critical of for years. Whereas on the diet that I recommend, your triglycerides go down as well as your LDL going down. You know, it's like the old story about Dr. Johnson's dog. The fact that it can stand on its hind legs is amazing even if it can't sing very well. The fact that it does anything well surprised a lot of people.

Now, HDL is another issue. Your HDL will go up on an Atkins diet, but that doesn't mean it's good for you. You know, your body makes HDL to get rid of excessive fat and cholesterol, and so if you feed someone a stick of butter, their HDL will go up because it's trying to get rid of it, but that doesn't mean it's good for you. In our studies we've found the HDL went down a little, the LDL went down much more, and they showed reversal of heart disease.

And that's the other problem with these studies, is that they haven't actually measured the underlying heart disease as we have. It makes me want to tear out what's left of my hair when I hear people say things like, "Oh, the Atkins diet is better for your heart than the diet that Dean Ornish recommends," when we've actually done studies to look at the underlying heart disease and find it's reversing, whereas the only studies that have been done on Atkins diet show that the heart disease actually gets worse.

Don't you think at this stage a lot of Americans are just totally confused? Because they hear what you say, they hear what Atkins says, they read totally conflicting advice in many ways.

That's the whole point of science, is to conflict claims by saying, "Show me the data." And I think the more thoughtful people are saying -- there is an emerging consensus that an optimal diet is low in the bad carbs -- in other words, low in the simple carbs -- but high in the good carbs, like fruits and vegetables and whole grains and legumes and soy products. It's low in total fat, and low in the bad fat, but it has enough of the good fats, like the omega-3 fatty acids, about 3 grams a day [is] all you need. It's low in the bad protein -- the animal protein -- but high in the protective plant-based protein. I think as we can all move towards a science-based, evidence-based consensus understanding, and still present a spectrum of how much people want to move in that direction. I think that, more than anything, can help people understand what they should be eating, without trying to sensationalize it in other directions. …















What do you feel when you hear people are as confused [about nutrition] as they've ever been?

Obviously I'm frustrated. I've spent my career trying to communicate sound nutrition information to the public. … I think that confusion about how they hear sound bites of information from science is real. What I think is probably not true is if they look themselves in the mirror and say, "What do I really know about nutrition," they know quite a bit. They know that they probably ought to not be eating very many saturated fats. They know that they need to eat a lot of whole grains and fruits and vegetables. And if you gave them 10 questions to answer, most people in this country, I argue, would be able to answer those questions. But I think what they're doing is backing off on, "Well, this is all too confusing, so I can't do any of it. I'm going to wait till the story is complete before I do very much."

I think that there is a little bit of a cop-out here, with all due respect. It's a different time in nutrition. When I started in my career, you couldn't get anybody interested in the subject. In fact, people thought I was nuts to go into the field in the first place. It wasn't on the public radar screen. It's very much on the public radar screen [now], so that every story is news, and the number of press releases, the number of articles, the coverage, the repeat coverage, it really does get it out into the public domain.

What is driving this interest in nutrition? Has it changed over time?

I think the interest in nutrition has changed dramatically over time. Remember that the part of nutrition that is really new news, going back 40 years now, is the idea that diet in some way could be involved in prolonging life, improving the length of life. I mean, the generation before that, or really the decades before that in nutrition, were all about preventing deficiencies and treating diseases. And now we have this whole new thing about how, "My gosh, how I eat could affect how many more weeks or months or years I live." That was really not front and center, up until the '50s -- until the '60s, really.


Jeanne Goldberg is a professor of nutrition at Tufts University's Friedman School of Nutrition. In this interview, she discusses how public interest in nutrition has changed over time in the U.S. She also addresses the public confusion over nutritional advice. "I think that confusion about how they hear sound bites of information from science is real," Goldberg tells FRONTLINE, but she says that the common sense Americans should use in approaching their diet is already ingrained from years of nutritional advice. "What I think is probably not true is if they look themselves in the mirror and say, 'What do I really know about nutrition,' they know quite a bit." This interview was conducted on Dec. 19, 2003.



What was nutritional advice like back in the '30s and '40s?

Well, there are some wonderful posters actually that go back to World War I, where the advice in fact, for very different reasons, was pretty much the advice we're giving now: Eat more whole grains. But it was because we wanted to reduce the inputs of energy into producing food. We want more food to send to the army. If you look at the series of public relations posters that were done in World War I, [it was] very close to what it is now.

What happened then of course in the '40s, we had rationing. People worried about the food supply, had to stand in lines to get butter, which everybody wanted. Margarine was certainly the poor alternative.

Then we came into a time of plenty. The idea was that a full plate of what some people have called the three-lump diet -- meat, potato, and vegetable on a plate -- was the idea of having arrived at what was the consummate healthy diet: healthy, big portion of meat, some starch to go with it, and maybe a little vegetable arrives on the plate.

The idea here is just having enough to eat?

Having enough of everything you eat. Certainly the notion of not being overweight was out there. I don't think anybody ever thought overweight was a desirable thing. It just wasn't such a problem, in large part because not only was the food supply more limited, a little bit less varied, but also people had to walk more. There was enforced physical activity. You walked to school; you walked home at midday, many kids for lunch, walked back to school for the afternoon session. That's four sessions of walking which there was no choice. Parents didn't have two cars [to] drop their kids off at school.

Multiply that small change, the shift from kids walking to school to riding to school, by the hundreds and thousands of other changes in our daily lives, and you get an equation which predicts imbalance in calories and the obesity problem that we're now facing.

This shift: How much is at stake when you start to think of diet in that way -- as a factor in health?

Well, the epidemiologists really can develop models which tell you exactly how many lives a year are likely to be saved, or how much the risk of disease and death is predicted by differences in consumption of fruits and vegetables and grains and saturated fat. Those numbers are really pretty big. It's decreases in cardiovascular disease deaths, decreases in cancer deaths, the big killers, osteoporosis, which is a major killer. And the irony of that is that osteoporosis is really a disease that begins in childhood, and is very well predicted by the amount of calcium that a kid puts down in their bones in the elementary school years up to teenage. It's not one we've thought of. It hasn't got as much publicity recently, but we now know that loading the skeleton with jumping, wild activities that kids really love to do if let loose to do them, giving them adequate intakes of calcium, will predict whether or not they get osteoporosis in later life, and that's a huge killer.

Talk about the change in the story.

The difference between eat to have enough -- and you need energy, you've worked hard in out in the cold, etc., etc. -- is very different than talking to the public about eating five servings of fruits and vegetables a day because there are big associations with decreased cancer risk, for example.

There are multiple problems with the latter message, and that is that surprise, surprise, there's a lot of the population that really doesn't pay a whole lot of attention to the relationship between what they eat and their health, and certainly not to long-term health. Taste swamps health as an indicator of what people choose by orders of magnitude. The cost: For a lot of the population, they simply look at a pound of meat and a pound of broccoli and they say, "They cost in the same ballpark. Why would I buy a pound of broccoli rather than a pound of meat? That's not what's going to keep my family full and happy, besides." So it's a very complicated set of issues. The health message simply does not resonate with a lot of the population.

But getting media exposure to these health messages is relatively easy. People want to know about diet and health, even if they don't act on the advice.

I think the issue of media exposure and media coverage has two sides to it. It has good side and it has a bad side. The media coverage, unfortunately, by and large -- and I'm talking now about news coverage, coverage of the science -- does not really give a story in context. "Eat more carrots as part of a diet which includes fruits, a lot of fruits and vegetables." That's a real snore. It's very hard to get across. And unfortunately, the message tends to get to be "Eat more carrots" one week, "Eat more tomatoes" the next week, often associated with a study that comes out: "Eat more tomatoes because tomatoes are an excellent source of lycopene, and our studies have shown that there's a decreased risk of prostate cancer associated with increased lycopene consumption." So that week it's tomatoes. It doesn't come out as: "Here's what the diet looks like, and here's what you ought to do as sort of the micro units of that diet."

The awareness of the link between saturated fat, cholesterol, heart disease -- why was this such a compelling story?

Well, the origins of the cardiovascular disease prevention possibilities of diet really lit up like a Christmas tree when Ancel Keys did this huge study in which you could show differences in cardiovascular risk associated with differences in diet. In diets which were low in fat, and then more clearly low in saturated fat, people just had less cardiovascular disease. The death rate was a lot lower. And then the studies evolved to look at people who were born in countries where the disease rates were low, and what happened to them when they came to the good old U.S.A. and assumed our diet. The disease risk changed dramatically. Guess what? They look like the rest of Americans within two generations. There was a complete wipeout of differences that were associated with their country of origin.

What makes you so sure it was the diet?

Well, one could say, "What makes us so sure it was the diet?" And I think we've said that. And I think it's not diet alone. It's a whole set of issues about diet and health.

One of the things that always gets lost in this story, I believe, is that, for God's sake, we're doing some things right, and we are living longer, and we are living with decreased risks of certain diseases. To be sure, a lot of that is related to better medications. But in fact, we eat a pretty good diet in terms of safety, for one thing. Many people are eating a perfectly healthy diet. It's not an all-or-none phenomenon. It's not that Americans are doing this or Americans are doing that. It's different segments of the population whose diet needs considerable improvement, and I think probably we have people at both ends of the curve, and most people in the middle of the curve. I think some of the population have made changes, others are way back at what we call the laggard stage, and others are at the innovation stages, where they're doing everything they possibly can to optimize their diet.

Talk about the fat story.

The fat story is really something of a small disaster in its evolution. And I think again there are multiple problems. One of them is the evolution of science. Originally, it was saturated fat, and then we began to understand more about which fatty acids it was. And also [in] the original story, cholesterol was a big player, and dietary cholesterol was associated with blood cholesterol. Well, it turns out that dietary cholesterol occurs in so much smaller amounts, its effect on serum cholesterol is not nearly as powerful as the effect of saturated fat. Well, that story, American consumers understood that cholesterol was bad. And the food manufacturers put "cholesterol-free" on every vegetable product they turned out. And if one did it, the other had to do it, because that's competition.

Then we learned, well, cholesterol wasn't the big player. It was saturated fat that really is the big player. From there we went on to types of fatty acids, and so we produce margarines with vegetable oils and the public begin to shift to margarines with vegetable oils. That's fine, and the whipped margarines have less saturated fat than the solid ones. And some of them have water whipped into them, and they have even less fat.

But then we looked and said, "Oh my gosh. In taking out saturated fat, manufacturers are using trans fats, which behave in the body like saturated fat." So the message that got out in the media was, "Butter is better than margarine." And there are headlines from a few years ago that say that. Many, many headlines. And that was one where the consumers just threw up their hands and said, "Oh my God, again they've pulled a dirty deal." It turns out that they both behave pretty much the same. And "less fat, more vegetable oil" is really still the message, which we started with. It's still the same message.

All baked goods would have trans fat?

A lot of baked goods have trans fats, except those that are made with butter, you know, which have the saturated fatty acids. Manufacturers have tried very hard, and are trying very hard, to get the trans fats out of their products. But I can tell you that what we call organoleptic factors, which is a funny, elaborate word for talking about mouth feel and the sensory qualities, and the cookies made without trans fats, to the very sensitive mouth, don't taste the same. Some people will tell you they do, and those who are really super-sensitive tasters will tell you that they don't.

I think a lot of this issue begs the question of a concept that Americans have a really hard time with. It's that concept of moderation. If we could eat two cookies and move on, we'd need a lot less of what I call this jiggering with the food supply. But we don't. We want to eat a lot of things, and a lot of what we eat, and a lot of variety.

And that's the other part of the fat story, which is that fat does have twice as many calories per gram as carbohydrate. So about 10 or 15 years ago, somehow we got this notion that: Aha. If we take the fat out of foods, we will be able to reduce the total caloric intake, and people will be able to control their weight. And so industry got very busy making low-fat, reduced-fat, fat-free products. And they flooded the marketplace and they flew off the shelves. And guess what? A lot of them weren't very good, and so they died on the vine very quickly. The ones that were good, people ate in excess. They didn't look at the portion size. They didn't look at the calories. They just ate them. There's no free lunch. There were calories. Guess what? People didn't lose weight. They got frustrated and went back to eating the food they liked in the first place.

What did [people think] when they saw "low fat, fat free"?

"Low-fat, fat-free, good for me. These have got to be good for me if they're marked low fat." Of course in many of the foods, if you looked at the label of the regular and the low fat -- and you can still do this -- the caloric difference isn't all that much. In some cases it's more significant than in others, but the issue is that if you take out fat, you got to put something in. That something, surprise surprise, has calories. It's most likely carbohydrate, a little bit of protein, and those both have calories. So you can't continue to take everything out and have some flavor and texture left, and the calories in many of those foods were not very different.

Some argue the simplification of advice [caused public confusion] and some argue nutritionists should have seen this coming. Where do you cast the blame?

I don't really want to cast blame on who's to blame for the confusion of the American public. I think we're probably all to blame. I think one of the problems, speaking for myself as a nutrition professional, is our tendency is to want to tell people the whole story, all at once, and change this to this, and this to that, and that to that -- a whole long menu of things that you should do. And the poor person on the receiving end of that, it's just overwhelming. It's just too much. So we've tried to throw the book at people a lot of the time.

I think another thing is that the public sector, which is charged with nutrition education writ large for the American public, has never had the kind of funding that it ought to have, to be doing the job. We haven't been able to compete in a consistent message with the private sector, which of course spends millions and billions of dollars on food advertising.

The food industry's behavior, is that not predictable?

I think the food industry is very resourceful. I was not intending to damn the food industry. In fact, one of the great ironies is that in the surgeon general's goals for the year 2000, the only goal in the nutrition arena that was met was the percentage of low-fat products that should be available to the American public by the year 2000. Industry was charged with producing those products. It was a government document that said industry should do this, and they did it.

Industry turns on a dime. They can do things quickly and resourcefully, and they gave it their best shot. Clearly, also, they were thinking in a competitive environment. That piece of it, in no way should anyone point a finger.

We failed through succeeding?

We've failed through succeeding in doing what was asked. Or industry failed through succeeding. If I ruled the world, I'd go back to basic foods entirely. But I don't rule the world.

You've also got the obesity community banging the low-fat drum.

Well, that was pretty consistently so until the people who were banging the low-carbohydrate drum came along. But actually, the people banging the low-carbohydrate drum began with -- I think his name was Dr. Banting, in 1862, who wrote a pamphlet called "A Letter on Corpulence," addressed to the general public, in which he proposed a low-carbohydrate, high-fat diet. … So the low-carbohydrate craze has been around a long time.

You can only practically jigger carbohydrates and fats. And what I honestly believe is that different diets work for different people -- work in the sense of if you need to lose weight, whatever is the most comfortable model for you to follow for a reasonable period of time, is probably what you ought to go with. The trick is what are you then going to stay with? It's not the weight loss. It's the weight maintenance which is the difficult thing. And I really believe that the low-carbohydrate, high-protein, high-fat mix is not the way to go long term.

Two anomalies: (1) in the low-fat era, people got fat; (2) people eating high-caloric food lost weight in the short term. The nutrition community wished this away?

Well, I don't think the nutrition community functions in lock step to have wished it away. It's a nutritionally imbalanced diet. I don't think anybody can really argue that one seriously. It is, as literally practiced, it's an atherogenic diet, it's followed long-term.

But I think the other thing is that nobody really looked at caloric intake over a long term. And I think we have not violated the law of thermodynamics. The fact is that while people are really excited about eating a steak-and-eggs diet at the outset, it gets old reasonably quickly. The people who've been successful on that diet really do cut back on their calories, so maybe they feel more satiated on a high-protein, high-fat diet, but they are not consuming appreciably fewer calories long term.

Satiety. You've got a diet with double the calories, but somehow you eat less.

That's because protein is digested more slowly. Fat has a very high satiety factor, and it does, for many people, allow them to feel more comfortable when dieting. Anyone who has ever deprived themselves of calories consciously has -- I haven't yet met the person who's said, "Oh boy, this is fun. I'm really enjoying it." The idea is: When can I get back to doing what I like to do? I think for most people, getting back to what they could do, what they like to do, if they'd only do a little bit less of it, it would be fine. The problem is, we go back to business as usual. It's very difficult in our environment to control weight. …

Is this a disaster?

My prediction is that the low-carbohydrate foods will, long run, be just about as successful as all the low-fat foods were. People are demanding them. Industry is responding to the demand. At the end of the day, it's not how people really want to eat. And really, food is fun, it's pleasure, it's what people like to do. These aberrant diets don't fit with what people really have become accustomed to, what they enjoy. It's not going to be the answer to the weight problem.

Are you saying all diets are artificial so they don't [work]?

No. What I'm saying is that the diet which sustains is probably a diet which is relatively higher in carbohydrate, complex carbohydrate, on the higher end in protein, and relatively low in fat.

But diet is only part of the story. You've got to put the exercise piece into the equation. Until recently, that's really been left out. It isn't that you can't burn off whatever you eat unless you're a marathoner and train all the time. But you do have to be physically active to manage to control your weight, unless you are willing to eat a very restricted diet.

Measuring what people eat and how much they exercise is a pretty hard thing to do.

It's extremely difficult to measure food intake and energy expenditure, and there's lots of error in the measurement. There's error in what people report. They can be as dedicated to reporting as they possibly think they can, but they can't possibly remember what they ate yesterday. They can't possibly accurately communicate what they usually eat. Those are difficult questions, and there are measures for validating what people tell you, but it's a very expensive technique and you can't do that sort of thing as field studies. So yes, there is error in measurement.

[Some] have criticized the USDA food pyramid as simplified. Would you defend the USDA pyramid?

I would defend the USDA food pyramid. In the interest of full disclosure, I have to say I was the principal investigator on the study which led to the release of the food guide pyramid after it was withdrawn.

I think one of the problems in the confusion about the food guide pyramid is that probably one person in 10,000 doesn't understand its origins. Its origins were as a graphic to explain the content of a booklet which laid out some of the specifics of the concept of variety, which was part of a government document called "The Dietary Guidelines for Americans." It was just a graphic that was supposed to illustrate some of these points. Somehow it got from that point into a debate which made it look like a policy document, as "This is one way to eat," and then there are a myriad of other pyramids which say, "This is the way to eat."

I wish the food guide pyramid were as powerful as its has been positioned as being, because if it were, and if Americans were following the food guide pyramid with the caloric bases on which it's underpinned, a lot of the obesity problem and a lot of the eating problems that we have would just go up in smoke. I think it isn't about whether it's the food guide pyramid or a pyramid that has a different configuration. We're just eating too much, and too much of the wrong things. But the food guide pyramid didn't cause obesity. It just is not that powerful.

One of the real problems in using it though is, if you look at the food guide pyramid, or any pyramid, it contains a bunch of basic foods -- breads, fruits and vegetables, dairy products, meat, so on. Everybody's seen it. The world is acquainted with it. What happens when somebody eats a pizza, which is a simple but very popular food? Where does that fit in the food guide pyramid? And what person is going to do the mental arithmetic to look at the food guide pyramid and say, "Okay, I had a pizza. Now, the crust belongs in the base. The tomatoes belong over here. The oil belongs at the top." You see where I'm going? I mean, all it is, is a graphic, which should be used as a tool that's part of a comprehensive learning program for kids and adults to learn how to choose a diet.

Some epidemiologists argue that all fat has been unfairly lumped in; that there should be a lot of fats at the bottom. Good[fat]-bad fat, good[carb]-bad carb.

… It's not a stand-alone graphic. There's a lot of information that goes into choosing a healthful diet. I don't care how good anyone is at designing graphics, they'll never put it into one triangle, pagoda, or any other model -- and we tried large numbers of models that might look more effective. I don't think that should be the use. I think we ought to come back to defining what is the use of the food guide pyramid, and begin from there. Wipe the slate clean and say: What are we going to do with this document? Or should we get rid of it?

Some people feel fats have got too bad a deal and carbs have got too good a deal -- [for example] the New York Times article. What is a nutritionist's response?

When we swing to the low-carbohydrate, low-fat, I think, "Oh no, not again." I really wish we could get a consistent message of balance intake and expenditure. Eat lots of whole grains, fruits and vegetables, limited amounts of fat.

I think for the public, really understanding all of this chemistry about trans fats and saturated fats, it runs counter to the way people choose a diet. If you go up to somebody in the supermarket and say, "Excuse me. Can you tell me whether you looked at the trans fat information? Or what information did you look at, on the food label?" The odds overwhelmingly are that they didn't look at the nutrition label. Many of the labels, they've looked at and learned about and moved on. But if they looked at anything, they looked at calories, and hopefully they looked at calories and serving sizes.

I think we really need to get back to helping people to understand what portions are. If we could get back to the portion issue, and understanding that the plate of spaghetti on the bottom of the food guide pyramid was never meant to be one serving of spaghetti. Many people looked at that and said, "Oh my God, if I ate six of those, I'd be like a house in a week." That was never the intent. The intent was to make a recognizable graphic that looked like pasta.

I think we're trying to throw too much at people, and we [should] really try to get back to a whole message about what should your diet look like over a week, and yes, it's okay to have some of your favorite foods some of the time, just not every day, all of the time, and as much as you like.

The idea that you can take a starchy food like a potato and it's turned into [sugar] very quickly, is genuinely novel, shocking to people.

… The problem with glycemic index is that it's extremely complicated. Setting aside whether controlling the spikes in blood sugar are a good idea or not, the form in which the food is cooked affects the glycemic index of the food. The mix of foods in which it's eaten affects the glycemic index. Measuring the glycemic index of carrots doesn't do any good unless you know what other foods the carrots are going to be eaten with.

So in my view, using glycemic index as something that we teach people how to live by is like selling them a pet rock. To me, it's unfathomable. It doesn't translate. Even if there is, down the road, proven to be some effect on controlling blood sugar more evenly throughout the day, I think we've got to be a little bit more practical about how we do it. And the notion of telling people to limit potato consumption -- I mean, yes, limit french fry consumption; yes, [don't] eat giant portions; but edging [potatoes] into a bad food category, to me, just doesn't make a whole lot of sense as a practical thing.

If part of the reason people overeat in a low-fat era is because of unrefined carbohydrates, through a physiological mechanism making them hungry, there is this question of what makes you hungry?

I'm not sure that we all agree that what makes you keep going back and eating is always hunger. I would say that a large part of it is that we have done a wonderful job of undermining the satiety mechanism. I don't think most of us realize that we've had enough and put down the fork. The notion of the clean plate club, which is a remnant of the postwar era, I think, and maybe even earlier than that, but we've overwhelmed the satiety mechanism. We eat too much because we're accustomed to it, we're served it. That doesn't have to do, I don't think, with glycemic index necessarily. I think that we need a retraining there, in terms of recognizing what's enough food, and what should be served as enough food.

Whether the concept of glycemic index can be translated into true meal planning, I have yet to be convinced of that. It's like all of the other very complicated things. Getting an entire population or a large part of the population to say, "Oh, I should plan my meal this way because my glycemic response will be lower," is not likely to go anywhere in large numbers very quickly. Even if it works for some people, it's going to be a very hard sell. It's going to be very difficult to do. Our food supply is so complex and so highly processed; this requires a cognitive load that most people aren't willing to take on. Their lives are complicated enough without it.

I also think that love of things like pasta are not going to be easily displaced. Now, having said that, the diet is too low in whole grains, and we really ought to work on stressing more whole grains and less refined carbohydrates. I think there's no question about that. The fiber content of the diet is way low. …

Over this period, the public health situation regarding obesity has become more and more alarming.

The rise in the prevalence of obesity, to me, is really scary. Maybe because I'm a nutritionist, it just scares me in terms of public health. I worry so much about all the gains that we've made in decreased incidence of cardiovascular disease and certain cancers -- we've done some good work. And with the rise in obesity, the rise in the early onset of type 2 diabetes -- it has been said many times, but we're just seeing the tip of the iceberg of a huge problem.

Probably the scariest part of that problem is the problem of obesity in kids. Because once kids become overweight and overweight to extreme, [it is] something they're not easily going to outgrow at adolescence; it's very difficult to reverse it. And you look at adults who are suffering in so many ways, and if you listen to their tales of how they can't fit in an airplane seat and all the rest of it, it's not the way they would prefer to live, but once having arrived there, very, very difficult to undo. It's going to be a huge public health burden unless we do something to reverse the trend.

Characterize type 2 diabetes.

Type 2 diabetes is a disease which we usually see in people in their mid-40s and older. Usually they're overweight, and if they lose a few pounds, very often you can get the symptoms to go away with the weight. Problem is, people get scared when they have a diagnosis, and they're real good for a short time, and then there is a high recidivism rate. But it has been typically a disease of middle-aged and older people, and it just has to do with the wearing out of the cells in the body that produce insulin so that there aren't enough, and they don't produce enough insulin. But now we're seeing this in kids. Now clearly, the kids in whom it's occurring, there must be a genetic predisposition to the expression of the disease at very much younger age.

But the problem is that it isn't the diabetes itself; it's the problems that are associated with uncontrolled diabetes long term -- devastating effects on the eyes, on the renal system, on the cardiovascular system. So it's not just about having diabetes and being on a diet, which unfortunately many of these people don't do. ...

As a society, are we facing a huge cost? Are we facing a generation that may not live as long?

We are facing huge medical costs. I mean, just the fact that we're beginning to have to treat kids for type 2 diabetes is just the tiniest, tiniest tip of the iceberg. The complications of obesity that are associated with type 2 diabetes, and the type 2 diabetes itself, will lead to increased incidence of blindness, kidney malfunction, and kidney decline and malfunction, more cardiovascular disease, and kids not living as long as their parents. But also, it's about quality of life, and I think we can't just talk about the end stage. We really need to talk about the fact that these kids, even though it's becoming more commonplace, the discrimination against kids who are overweight is right out there, just like it was when I was a kid.

Solutions? Does it seem hopeless?

Well, I'm an optimist. And I know that we're going to get on top of this problem. We have got to. It's too urgent a public health problem. It's too pervasive in our society. We're not going to build wider airplanes and all the rest of it, and wider seats on buses, to accommodate. That's just really a band-aid approach.

I think we need vast environmental changes. We need individuals to recognize that they've got to take ownership of the problem, because at the end of the day, it's the calories you put [in] your mouth and the energy that you burn, walking to get a newspaper, or don't burn by riding to get a newspaper, that really make the difference.

On the other hand, we also have to make it possible for kids to get lots of physical activity. That is not available to kids now, for a bunch of reasons. I think right now there are lots of good programs, many of them funded as research projects -- we have one ourselves in Somerville, [Mass.] called "Shape Up, Somerville" -- which are trying to change the environment to create a healthy environment, so that everything about the day provides opportunities for healthier choices.

I don't think there's one solution. But I think that encouraging kids to walk to school, and if it's not safe to walk alone, creating mechanisms by which they can walk in groups, is one teeny little thing, but it's a piece of something that we threw away without looking back. I think parents of very young kids have got to get them out of those little strollers that they use until ages way past when -- certainly when I pushed my kids around, and most other people did. It's convenient, it's fast, it's easy, and the kids are riding around in buggies until they're 7 and 8 years old, and some even older, because it's convenient.

There are a myriad of small things that need to be done: Parks cleaned up so kids can play in them, in all communities. The Rails to Trails program, converting bike routes, bike paths, so we have safe places to bicycle. We need more opportunities to make outdoor activity a way of life. We need school recess. We need activity programs in after-school programs. We need to make activity part of daily life.

That's the expenditure side.

That's the expenditure side. We also need to have food environments with healthy choices, all the time. Airports are a great place. Actually there is some small trend in the direction of being able to get something reasonable in an airport, but most airports most of the time are travesty on nutritional balance. School lunches need to be real healthful meals with foods that kids like to eat. They should not be fried nuggets and hot dogs and little else. Fried nuggets and hot dogs are okay some of the time, but not all the time. The snack line certainly needs to have lower fat choices, more healthful choices for kids. There are loads and loads of small things we can do. There isn't one solution.

What about family meals? Is that just hopeless?

I think family meals are extraordinarily important, and I think the notion that nobody ever has time to sit down is silly. It's as silly a notion as the fact that nobody understands what they ought to eat. People can make time, and they can make it a value. The family meal table needs to be a place where people get together and exchange ideas. It's part of a set of values. I don't think it's reasonable to basically let the eating process take itself where it may. "There's a microwave, there's food in the freezer, eat what you want," is not okay. I think that's probably the extreme. I certainly have witnessed it. But I like the other extreme, which is the family sits down to dinner every night. [If] they can't sit down to dinner every night, and everybody eats the same thing, and meals are meals and snacks are snacks, and people know the difference, they can certainly do it some of the time.

Can you draw a distinction between diet [and weight maintenance]?

Well, a weight-loss diet has got to be a diet that has a caloric deficit, that is, one where you consume fewer calories than you burn. And that requires a conscious attempt at seeing where you are. I think what happens is that people say, "Okay, I'm going to go on a diet," and they react by putting themselves on some semi-starvation thing. "I'm going to accomplish all this in an unreasonably short period of time. If not by tomorrow, at least in 3 weeks." It doesn't work, because they're so hungry and so miserable, and don't like themselves, that the rebound effect is really terrible. They often gain back more weight than they lost in the first place.

The weight reduction diet really should begin with a goal: It is reasonable for me to lose a pound a week if you're older, 2 pounds a week if you're younger. But it's got to be a combination of assessing what you eat and cutting back on that, and assessing what you do to move, and adding to that. Once you get to maintenance, the idea is to do some monitoring. You can add things back, but to do some sort of monitoring so that you realize that when you're a pound or two over, whoa, this is the time to go back. Not when you're 5 pounds over or 10 pounds over. The longer you wait to pull in the reins, the harder it gets, but I think most people who are in a phase of maintenance will tell you that they never stop keeping track of what they're doing.

You can't let up.

I think saying you can't let up is a little bit harsh. That makes it like a life sentence. I think keeping it somewhere in your consciousness that if you're going out to dinner at night, you eat a light lunch. It's not brain surgery. It's just common sense.