Weight loss and regain and effects on body composition: the Health, Aging, and Body Composition Study.

BACKGROUND Older adults are less able to conserve lean mass relative to fat mass with weight change. A cycle of weight loss and regain in an older individual could accelerate sarcopenia. We examined whether older adults experiencing weight loss and regain would show a greater loss of lean mass during a weight-loss period than gain in lean mass during the weight-regain period, thus have overall a greater net loss of lean mass compared with those who maintained weight in the Health, Aging, and Body Composition Study. METHODS We compared the body composition change in 147 older weight changers (54% women, 38% black) with the gender- and race-matched weight-stable individuals over the weight-cycling period. A weight cycle was defined as weight loss of 3% or more with regain of within +/-3% of baseline weight for a period of 2 years. RESULTS Both men and women showed significantly lower total body mass after the weight loss and regain. Proportionally, more lean mass was lost during the weight-loss period than was gained during the weight-regain period, especially in men. After weight regain, men showed only a slightly lower lean mass than the stable group, and this was not statistically significant, although the failure to fully regain total weight explained most of the deficit in lean mass after the weight cycle. CONCLUSION These data suggest that weight loss even with regain may contribute to a net loss of lean mass in older men but warrant further studies.