Q: I have heard conflicting stories about the possible dangers of repeatedly losing weight and then regaining it. Does such a pattern pose health risks?
A: Several years ago newspaper headlines accompanied articles that emphasized the dangers of weight cycling, also called "yo-yo dieting" as a graphic description of the repeated ups and downs in weight common among dieters. Some obese people have cited such studies as their reason for not initiating another weight-loss program. A National Task Force on the Prevention and Treatment of Obesity, sponsored by the National Institutes of Health, addressed this issue in a report published in a recent issue of the Journal of the American Medical Association. The conclusions were based on a review of 43 scientific articles dealing with research on the subject. Previous researchers had attributed three major ill effects to weight cycling: adverse metabolic effects, increased incidence of heart attacks and death from coronary disease and other causes and harmful psychological effects. The proposed adverse metabolic effects
included greater difficulty in losing weight after each cycle of weight loss and regain; reduced basal metabolic rate (which would tend to make weight loss more difficult); and a redistribution of body fat to favor its accumulation in the abdominal area (abdominal fat is more likely than hip fat to be associated with diabetes, high blood pressure and heart disease).
The task force concluded that the available evidence did not support the contention that yo-yo dieting interferes with the effectiveness of subsequent attempts to lose weight, alters metabolic rate or changes the distribution of body fat. Nor were the members convinced that weight cycling increased the risk of cardiovascular disease or death from other causes. Although it is obviously distressful to repeatedly fail in attempts to achieve permanent weight loss, the task force could find no valid data showing any significant psychological ill effects of weight cycling.
Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine.