Weight Loss and Lean Body Weight Maintenance (Exercise, Diet, Weight Training).

Two experiments were completed to determine the effects of exercise on lean body weight (LBW) during periods of calorically-induced weight loss. In the first experiment, 10 subjects (6 women, 4 men) were r and omly divided into diet-only (DO) and diet-plus-exercise (DPE) groups. Caloric intakes for dietary subjects in both studies were reduced by 1000 kcal/day from baseline. Exercise consisted of 3 days/week of mild aerobic exercise and 3 days/week of weight training. Body weight decreased significantly (p < 0.05) for the DO (-4.80 kg) and DPE (-6.0 kg) groups. LBW decreased significantly for the DPE group (-1.60 kg) with a non-significant decrease (-0.20 kg) for the DO group. In the second experiment, 40 obese women underwent an 8 week diet and exercise program. Subjects were divided into control (C), DO, DPE and exercise-only (EO) groups. Weight training exercise was used exclusively in this experiment and consisted of three sets of 8 exercises, 3 days/week. Body weight decreased significantly for DO (-4.47 kg) and DPE (-3.89 kg) compared to C (-0.38 kg) and EO (0.45 kg). LBW increased significantly for EO (1.07 kg) compared to DO (-0.91 kg) and C (-0.27 kg) and for DPE (0.44) compared to DO. Upper-arm muscle area (X-ray measurements) increased significantly for DPE (11.23 cm('2)) and EO (10.44 cm('2)) compared to C (2.69 cm('2)) and DO (2.10 cm('2)). One repetition maximum bench press strength improved significantly for DPE (5.31 kg) and EO (4.77 kg) compared to C (1.13 kg) and DO (-0.69 kg). Results of the two studies lead to the following conclusions: (1) Adding aerobic exercise to a caloric restriction program exacerbates losses of LBW. (2) The addition of weight training to a program of mild caloric restriction results in specific regional muscular hypertrophy. (3) Weight training-induced strength gains are not affected by moderate caloric restriction. (4) The addition of weight training to a program of mild caloric restriction results in maintenance of the LBW component. (5) There are no diet-by-exercise interactions during weight loss. This suggests that the effects of diet and exercise are additive.Ph.D.Physical educationAnimal PhysiologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/161201/1/8702677.pd