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 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.
JAMA, Journal of the American Medical Association
RELATED PAGE LINKS
Facts & Figures
Health At Every Size
Take Good Care of Yourself
Long Term Diet Failure (currently open)
Barriers to Treatment: A Patient’s View
Food & Exercise
Feminism & Weight
Eating & Exercise