For years doctors have held that the only way to lose weight is to eat less fat and take more exercise. But now an eminent science writer says they've got it wrong. So, asks Melissa Whitworth, could Atkins have been right all along?
As you pound the treadmill in the gym, trying to sweat off the Christmas pudding and wind back the dial on the bathroom scales, consider this: what if someone told you it was all in vain? What if no amount of exercise will make you thinner, and everything we've been led to believe about exercise, diet and obesity is wrong?
This intriguing possibility has been raised by Gary Taubes, America's most controversial science writer and the author of a book called The Diet Delusion: Challenging the Conventional Wisdom on Diet, Weight Loss and Disease. The book, out this month, tackles what Taubes says are the myths surrounding these issues. Taubes, believes that, since the obesity epidemic began, back in the late 1970s, scientists have been working with faulty - or at the very least too little - data. After conducting his own research for 13 years he has some shocking conclusions: exercise won't make us thin; carbohydrates are what cause obesity; eating fat doesn't cause heart disease.
We meet in Taubes's office in the New York flat he shares with his wife, who is an artist, and their two-year-old son. One of America's most respected science writers, Taubes has contributed to the prestigious magazine Science for 16 years, writes for the New York Times and the Atlantic and has won the National Association of Science Writers award three times. At 6ft 4in with salt-and-pepper hair and more than a passing resemblance to a young Kirk Douglas, Taubes is more jock than science nerd and says he spent a lot of his time at university - Harvard, Stanford, then Columbia - playing sport.
One of the central arguments in Taubes's book is that some people are genetically predisposed to be overweight and that no amount of exercise will change this. Some of us have bodies that want to burn calories; others store them as fat. Taubes believes the all-important relationship between carbohydrates and insulin and the way they affect fat tissue and obesity have been forgotten - or conveniently ignored - in scientific debates about obesity. According to him, carbs are indeed the enemy.
'The natural question is, "What regulates fat accumulation?"' he begins, swivelling gently in his office chair. 'That was actually worked out 50 years ago. We know that the hormone insulin is what puts fat in fat tissue. Raise insulin levels and you accumulate fat; lower insulin levels and you lose fat. And we secrete insulin as a response to carbohydrates in the diet.
'We have screwed up the causality of obesity,' he continues. 'Fat people are predisposed to be fat. Genetics determines how we respond to the carbohydrates. Healthy people exercise more than unhealthy people, and we know that lean people exercise more than heavy people - but that doesn't tell us that exercise will make a heavy person lean or an unhealthy person healthy.'
Taubes's defence of a high-fat, low-carb regime sounds suspiciously like the Atkins diet, which proposed that a hefty slab of steak followed by cheese was less fattening than a bagel or a bowl of pasta. The Atkins diet still has many fans, but recently seemed to have been consigned to the reject bin among health warnings and heart-attack alerts (and the news that when Dr Atkins died in 2003 he was a hefty 18½ stone). But in his book Taubes puts forward a compelling case for avoiding a high-carb, low-fat diet. 'I have this problem when I talk to physicians and biologists, ' he says. ' They will say, "OK, I can see that obesity is a disorder of fat accumulation. I acknowledge insulin makes us store fat." Then I say, "Well, that implicates carbohydrates," and they go, "Oh, that's that Atkins crap. It's old news." They shut down and that's the end of the discussion.' In fact, he says there are many respected scientists who do agree with him, but who are reluctant to support him openly.
In 2002 Taubes wrote an article for the New York Times Magazine called 'What If It's All Been a Big Fat Lie?' The article made him famous for making Dr Atkins popular again, and caused uproar in the medical community. Not only did Taubes's research seem to show that the controversial diet was best for losing weight, it also showed that the diet improved cholesterol profiles, too - the exact opposite of what its critics said it would do. The Atkins diet book jumped from number 178 to number five on Amazon's bestseller list.
'I got actively attacked, but I guess I had to be,' Taubes says. 'What are the chances of writing an article that says the entire medical establishment is wrong, and them going, " Good point, thank you, Gary. Can we give you an award?" When people challenge the establishment, 99.9 per cent of the time they are wrong. If I was writing about me, I'd begin from the assumption that I am both wrong and a quack.'
So why should we listen to him? Taubes is not a scientist, so rather than conducting his own trials, he has re-examined existing research with fresh eyes. His conclusions are therefore based on information that was already out there but was being ignored. ' I bought the conference proceedings for every obesity conference held prior to the late 1980s - at which point they happen so frequently it's overwhelming. ' Reading these papers, he noticed discussions of an enzyme called lipoprotein lipase (LPL), a subject dealt with in his book.
'The job of determining how fuels will be used - whether we will store them as fat or burn them for energy - is carried out by the hormone insulin with LPL,' says Taubes. 'Because insulin determines fat accumulation, it's quite possible that we get fat not because we eat too much or exercise too little, but because we secrete too much insulin. As it turns out, it's carbohydrates that primarily stimulate insulin secretion.'
Taubes has also looked again at how LPL behaves during exercise. Once we finish our workout, LPL goes to work sucking calories back into fat tissue to recoup lost energy. And we feel hungry. This is one reason Taubes believes exercise can never be that effective in helping us lose weight. 'The feeling of hunger is the brain's way of trying to satisfy the body's demands. ' The insignificant energy we might expend at the gym, Taubes says, has a negligible impact on weight and is easily undone by small changes in what we eat. Strenuous exercise only makes us hungrier.
'Reading the research was a reawakening for me,' he says. 'I did all the things that the rest of us did. I ate a low-fat diet, went to the gym and was getting heavier anyway. But once you flip your way of thinking about it, it seems so absurd: the idea that what you put in minus what you expend equals how fat you are. Our bodies don't work like a car. We are not thermodynamic black boxes; we are biological organisms and we have evolved complex systems of hormones and enzymes and proteins. That's how we are regulated.'
The obesity epidemic began in America during the late 1970s, which is also when the low-fat, high-carb diet-and-exercise revolution began. 'You have a starting point,' says Taubes. 'The question is what is causing it? Then I realised that we were first told to eat less fat in the late 1970s, and, if you eat less fat, you start to eat more carbohydrates - it's a trade-off.'
Before that point, the medical profession's attitude to obesity was more in line with Taubes's thinking. In 1932 Russell Wilder, an obesity specialist at the Mayo Clinic, said his patients lost more weight with bed rest than with exercise. In 1942 Louis Newburgh of the University of Michigan calculated that a 17½-stone man would have to climb 20 flights of stairs to rid himself of the energy contained in one slice of bread.
'Pasta, bread, potatoes, rice, beer - these were the foods my mother's generation believed were fattening. If you went on a diet 50 years ago, that's what you gave up. '
So, I ask Taubes, I eat tons of carbohydrates, how come I'm not fat? 'Well, the world is full of people like that,' he replies. 'A good metaphor is cigarettes and lung cancer - 95 per cent of people who get lung cancer get it because they smoke. Not all people who smoke get lung cancer. The other fact is you are not fat yet.'
For all the controversy, Taubes remains jocular. He says he's been 'an athlete and a chronic exerciser my whole life', does yoga twice a week and visits the gym. But does he ever worry about being wrong? Taubes says he is more worried about being ignored or having his arguments dismissed as unworthy of public debate. But then he admits, 'I have a friend who says that, if I'm wrong, I will have to live in Argentina with all the other mass murderers. Though there is good meat in Argentina. Look,' he continues. ' All I did was follow the data. It boggles my mind that it brought me to this place where I am trying to convince the medical establishment they screwed up the biggest health issue of this half-century.'
Weight-loss the Taubes way
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