Weight Regain and Hormones

A new study of postmenopausal women found that older women who lose weight tend to gain it back again, and as fat rather than muscle. At the start of the study, the 78 women with an average age of 58, had lost about twelve percent of their body weight. Six months later, 68 percent of the women had put back on some of their lost weight and after a year, 76 percent of the women had regained some of their lost weight. Sixteen percent of the women were heavier at the 12-month follow-up than at the start, and just under a quarter of the women had continued to lose weight. After evaluating the type of body mass that constituted their weight gain, the researchers found that fat was regained far faster than muscle in the postmenopausal women.

Perhaps this weight gain occurs because after dieting, hormones change that fuel weight regain. Earlier this year, a study published in the New England Journal of Medicine, found that hunger-related hormones, such as leptin and ghrelin, were disrupted by dieting. According to an article about the study, the findings indicated that hormones can remain at altered levels for at least a year, stimulating a heartier-than-normal appetite and spoiling even the best intentions of dieters. The study put obese individuals on a low-calorie diet for 10 weeks and then followed the participants for a year, tracking their hormone levels. After they lost on average 30 pounds on the diet, blood tests showed that several hormone levels–leptin, ghrelin, and insulin–had changed as a result of the weight loss. The participants felt hungrier before and after breakfast than they had been at the beginning of the study. After a year the group members had regained on average 12 pounds, and tests showed that their hormone levels had only partially stabilized and their hunger levels remained elevated. The hormone changes would be expected to stimulate weight regain. The study authors concluded that “in obese persons who have lost weight, multiple compensatory mechanisms encouraging weight gain, which persist for at least one year, must be overcome in order to maintain weight loss. These mechanisms would be advantageous for a lean person in an environment where food was scarce, but in an environment in which energy-dense food is abundant and physical activity is largely unnecessary, the high rate of relapse after weight loss is not surprising.” They said the findings also suggest that there’s an elevated body weight “set point” in obese patients, and efforts to lower weight beyond this point are biologically “vigorously resisted.”

The researchers also noted that weight loss surgery has been shown to have positive effects on hunger hormones, but surgery isn’t readily available to many patients. It is not covered by insurance for many people, but some obesity experts are pushing to extend coverage. Just this week there was an article published about medical device makers urging the U.S. government and health insurers to cover weight-loss surgery, an effort that could give millions more obese Americans access to the treatments.

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