Objective: Numerous reports have suggested that cycles of weight loss and regain (i.e. , weight cycling) are associated with adverse health consequences, a concern that may lead some obese individuals to forgo weight control efforts. The present study examined whether weight cycling was associated with a reduction in resting energy expenditure ( R E ) and with increases in both total and upper body fat. Method: REβ¬, body composition, and body fat distribution were measured before and after weight loss, and following full weight regain, in 12 women who before treatment had a mean ( S E M ) age of 38.8 2 3.4 years and weight of 98.0 -+ 3.2 kg. Results: At the end of treatment, patients lost 18.9 ? 2.6 kg which was comprised of significant decreases in body fat and fat-free mass of 15.2 ? 2.2 and3.7 ? 0.8 kg, respectively (both ps < .OOl). REE also fell during this time from 1,631 ? 82 to 1,501 2 51 kcalld (p < .03). All of these measures, however, returned to their baseline values when patients regained their lost weight. Body fat distribution was unchanged throughout the study. Discussion: These results do not support claims that weight cycling adversely affects REE, body composition, or body fat distribution. 0 7996 by