By Kathleen Doheny
"We found that low-fat diets were not more effective than higher-fat diets for long-term weight loss," said study leader Deirdre Tobias, an associate epidemiologist at Harvard Medical School and Brigham and Women's Hospital in Boston.
The key to success seems to have more to do with adherence than a specific weight-loss plan, Tobias said. "Being able to stick to a diet in the long term will probably predict whether or not a diet is successful for weight loss," she said.
The new analysis was published online Oct. 30 in The Lancet Diabetes & Endocrinology journal. The research was supported by the American Diabetes Association and the U.S. National Institutes of Health.
In conducting their analysis, Tobias and her colleagues looked at 53 published studies involving more than 68,000 adults. Those on low-fat diets did lose weight. But, those on low-carbohydrate diets were slightly more than 2 pounds lighter than those on low-fat diets after a follow-up of at least one year. The average weight loss across all groups was 6 pounds, the researchers said.
The take-home message, Tobias said, is not to eat fatty foods with abandon. Rather, there are a variety of weight-loss plans and "there isn't one that floats to the surface as the optimal diet for weight loss."
She advised that anyone wanting to lose weight find a sound weight-loss program that fits their preferences and cultural needs.
The low-fat diets in the studies ranged from very low-fat, 10 percent or less of calories from fat, to more moderate plans that allowed 30 percent or less of calories from fat.
Connie Diekman is director of university nutrition at Washington University in St. Louis. She said, "The result of this study on diet composition and weight loss seems to support results that have been observed in other studies.
"The conclusion from this, and similar studies, is that weight loss is not a result of limiting one calorie nutrient over another, and that achieving weight loss is likely a matter of calorie control, in a manner that works for the individual," she added.
Diekman said the study did have several limitations. Among them: many of the studies included in the review had "high levels of subjects drop out, making it difficult to know if the diet itself made adherence challenging."
For successful weight loss, Diekman advises talking with a registered dietitian "who can design an eating plan for weight loss that meets your lifestyle."
Add physical activity to your daily routine, she added, and think about weight loss as part of your long-term health goals, and not just a quick fix.