Omega-3 Fatty Acids: Weight Loss Aids?

Learn whether weight loss is one of the benefits gained by eating more omega-3s.

By Madeline Vann, MPH

Medically reviewed by Pat F. Bass III, MD, MPH

Veterans of the weight-loss wars are likely familiar with omega-3 fatty acids as the “healthy fats” touted in some popular diets as being both beneficial to overall health — particularly heart health — and a boon for weight loss.

Omega-3 is shorthand for the more correct term “long chain omega-3 polyunsaturated fatty acids” or “n-3 polyunsaturated fatty acids (PUFA).” They are found in deep-sea fish such as salmon, mackerel, swordfish, and shark as well as certain oils (canola) and nuts (walnuts). There are three types of omega-3 fatty acids:

• Alpha-linoleic acid (ALA)
• Eicosapentaenoic acid (EPA)
• Docosahexaenoic acid (DHA)

Omega-3 Fatty Acids in Weight-Loss Plans

Here’s how popular diet plans stack up in terms of the amount of omega-3 they suggest:

• The USDA Food Guide Pyramid recommends between 1 and 3 grams of omega-3 per day.
• The Zone diet and the Atkins diet each recommend between 3 and 4 grams per day.
• The Ornish plan keeps omega-3 to 1 gram or less per day.

Studies have shown that diet success depends more on calorie reduction than the specific plan you follow, so naturally if your goal is weight loss, you might be wondering whether the amount of omega-3 foods in your diet makes a difference.

According to researcher Mario Kratz, PhD, assistant member, Fred Hutchinson Cancer Research Center, and research assistant professor at the University of Washington in Seattle, the answer is that, despite their other health benefits, omega-3 fatty acids do not have a direct effect on weight loss.

Many studies have shown that people can lose weight on diets with an emphasis on omega-3, says Kratz, but when his team conducted a trial comparing the weight loss of two groups of overweight people who ate exactly the same foods with the exception of the types of fats used to prepare the foods (omega-3s vs. saturated fats), they found no difference in weight loss between the two.

“Omega-3s may help with other health consequences of being obese, such as heart disease, but in terms of these fats specifically helping you to lose weight, I’d say if there is any effect it’s probably minimal and it doesn’t play a clinical role,” says Kratz.

Why You Should Include Omega-3 Fatty Acids in Your Diet

Research into the weight-loss benefit of these healthy fats is still ongoing, the current theory being that these fats:

• Improve glucose sensitivity
• Reduce insulin resistance
• Reduce markers of inflammation
• Speed fat oxidation by stimulating a specific receptor in the liver that affects fat

All of this means that if you include some fat in your diet, choosing omega-3 fatty acids is better for weight management than foods containing saturated fats. On a practical level, this means your weight-loss goals could benefit from choosing salmon for dinner over beef or from preparing foods with canola oil instead of butter.

More Health Benefits of Omega-3 Fatty Acids

Even if increasing omega-3 foods won’t accelerate weight loss, there are many health benefits to including them in your diet:

• Lower triglycerides
• Lower blood pressure
• Slow atherosclerosis
• Reduce heart attack and stroke risk
• Improve symptoms of arthritis

Building a Weight Loss Diet with Omega-3 Fatty Acids

The changes you will make to increase omega-3 fatty acids in your diet should complement your weight-loss plan. Consider including more of these foods with omega-3 fatty acids:

• Fatty fish including salmon, tuna, and mackerel
• Leafy green vegetables
• Vegetable oils such as canola, flaxseed, and soybean
• Nuts, with walnuts at the top of the list

Although it would be difficult to eat enough fish to get excess calories from adding omega-3 foods, you certainly could go overboard with nuts and oils, so stick to the minimum you need. Take a supplement to amp up your omega-3 intake without the calorie load. Supplements offer the same health benefits without the added calories.

Even if omega-3 fatty acids do not cause weight loss, there are many health benefits to including them in your diet — and better health is at the core of why you want to lose weight.