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This study investigated whether the addition of the high-intensity sweetener aspartame to a multidisciplinary weight-control program would improve weight loss and long-term control of body weight. One hundred sixty-three obese women were randomly assigned to consume or to abstain from aspartame-sweetened foods and beverages during 16 wk of a 19-wk weight-reduction program (active weight loss), a 1-y maintenance program, and a 2-y follow-up period. Women in both treatment groups lost [approximately equals] 10% of initial body weight (10 kg) during active weight loss. Among women assigned to the aspartame-treatment group, aspartame intake was positively correlated with percentage weight loss during active weight loss (r = 0.32, P [is less than] 0.01). During maintenance and follow-up, participants in the aspartame group experienced a 2.6% (2.6 kg) and 4.6% (4.6 kg) regain of initial body weight after 71 and 175 wk, respectively, whereas those in the no-aspartame group gained an average of 5.4% (5.4 kg) and 9.4% (9.4 kg), respectively. The aspartame group lost significantly more weight overall (P = 0.028) and regained significantly less weight during maintenance and follow-up (P = 0.046) than did the no-aspartame group. Percentage weight losses at 71 and 175 wk were also positively correlated with exercise (r = 0.32, P [is less than] 0.001; and r = 0.34, P [is less than] 0.01, respectively) and self-reported eating control (r = 0.37, P [is less than] 0.001; and r = 0.33, P [is less than] 0.01, respectively). These data suggest that participation in a multidisciplinary weight-control program that includes aspartame may facilitate the long-term maintenance of reduced body weight.

This study examined the influence of initial degree of obesity on loss of fat-free mass (FFM). One hundred twelve obese females participated in a series of very-low-energy diet (VLED) clinical trials. Obesity groups were determined by three common methods. percent body fat, body mass index, and weight. Within each group, subjects were classified into low-, intermediate-, and high-obesity groups. As expected, the high-obesity group lost comparable amounts or more weight and more fat weight than the low- and intermediate-obesity classifications for each group. The high-obesity group lost [is nearly equal to]] 2% more FFM (P < 0.05) compared with the low and intermediate group when subjects were grouped by body mass index and weight and showed no differences between classifications when subjects were grouped by percent body fat. No differences were found between classifications for ratios of FFM to weight loss regardless of how subjects were grouped. Thus, the degree of obesity does not seem to affect loss of FFM.

Effect of large (LA; 400 min/wk) and moderate (MA; 200 min/wk amounts of endurance exercise in combination with weight training (3 d/wk) were compared with the effects of no exercise (C) in 23 obese females after a 12-wk, 3360-kJ/d very-low-energy diet (VLED). The LA group lost 6.5 kg more weight, mainly as fat (6.4 kg), than the C group (P

The combined effects of exercise and energy restriction on changes in body fat and fat-free mass (FFM) are controversial. This study was conducted to determine whether muscle hypertrophy is possible during weight loss. Fourteen obese females received a 3360-kJ/d liquid diet for 90 d. Seven subjects received a weight training (WT) regimen and seven subjects remained sedentary (CC). Biopsy samples were obtained from the vastus lateralis muscle at baseline and after 90 d of treatment. The average weight loss over the 90-d period was 16 kg with [is nearly equal] 24% of the weight loss from FFM and 76% from fat. The amount and composition of the weight loss did not differ between WT and C groups. The cross-sectional area of slow twitch and fast twitch fibers was unchanged by treatment in C subjects but significantly increased in WT subjects. It appears that weight training can produce hypertrophy in skeletal muscle during severe energy restriction and large-scale weight loss.