April 18, 2003

Researchers finally did a rigorous, fairly long-term study of the effectiveness of a specific diet. While most diet studies stop after a few months to a year, in this instance scientists observed dieters' progress over two full years. The study was a carefully done, multi-center randomized clinical trial, and scientists at six academic research centers around the country took part.

One of the tenets of the Health At Every Size movement in general, and The Council on Size and Weight Discrimination in particular, is that weight-loss diets are at best a temporary fix. Commercial diet programs mislead the public by failing to produce evidence of their long-term effectiveness. The Council's Director of Medical Advocacy, Lynn McAfee, attends meetings of several government agencies that fund or oversee research (e.g. the NIH, FTC, and FDA) as a consumer advocate. She has been actively stressing the need for long-term studies for many years. It seems our message is finally being heeded.

The study, reported in JAMA, compared two-year weight loss among 65 men and 358 women of various weights (but all considered "obese"), randomly assigned to either a Weight Watchers program (weekly meetings, a food plan, an activity plan, and behavior modification, all provided for free) or a self-help program (two twenty-minute counseling sessions with a nutritionist and provision of self-help resources). After the first year, the average weight loss was about 9.5 pounds on Weight Watchers, versus just under 3 pounds on self-help. But at the two year mark, the average participant had regained some of the weight lost, so the net loss was 6.4 pounds for Weight Watchers versus one-half of one pound for self-help.

Although the research team drew the conclusion that Weight Watchers was "more effective" than self-help, it doesn't take a degree in statistics to realize that the diet program failed to produce a lasting significant weight loss. This is the first real clinical proof of what we have been saying all along: diets are not effective as a long-term strategy for weight loss, in part because people regain most or all of the weight they lose. If the scientists had followed their subjects for another three years, we are certain that the weight regain would have been even more dramatic.

Although this is disappointing news for those looking for a way to lose weight, we feel it may be the beginning of a new era in research. We hope more studies will follow participants for two years, and even longer, so that meaningful results can be obtained. Perhaps they will begin to acknowledge that reducing diets as they stand now are a dead end. And perhaps they will put more emphasis on the much-needed research into the underlying basic biological mechanisms that affect body weight, appetite, metabolism, and weight gain, loss, and regain.

Thanks to all those in the HAES movement who stood up for long-term studies. We can count this one as a victory. Research in the future will have to live up to the two-year standard set by this important study.

For a free abstract, or to purchase a copy of the full text of the study, see below.

Weight Loss With Self-help Compared With a Structured Commercial Program: A Randomized Trial. Stanley Heshka, James W. Anderson, Richard L. Atkinson, Frank L. Greenway, James O. Hill, Stephen D. Phinney, Ronette L. Kolotkin, Karen Miller-Kovach, and F. Xavier Pi-Sunyer JAMA 2003;289 1792-1798

http://jama.ama-assn.org/cgi/content/abstract/289/14/1792?etoc