The effect of exercise on energy intake and body composition in overweight women

Twelve moderately overweight women with mild obesity were studied to determine the effect of exercise on nutrient intake and body composition. The women, 16 to 42 percent above desired body weight (BW) and 30 to 41 percent body fat, rotated through three 18-day treatment periods: no exercise (NO-EX), moderate duration exercise (M-EX), and long duration exercise (L-EX). Daily exercise was prescribed to increase energy expenditure by 12.5 (M-EX) or 25 percent (L-EX) of energy intake required for BW maintenance during baseline. Diets were self-selected from a variety of conventional foods, and intake was monitored. Exercise did not affect quantity of energy intake or macronutrient composition of diets during the treatment periods. Energy and carbohydrate intakes tended to be higher in response to M-EX and L-EX compared to NO-EX during the last 5-day interval of the treatment periods, but these trends were not statistically significant. Exercise did affect BW and fat-free mass (FFM); mean FFM values were 49.3, 49.7 and 50.8 kg at the end of NO-EX, M-EX and L-EX, respectively (P = 0.017). Body fat mass (FM) was not consistently affected by exercise. It appears that exercise affects FFM but has no consistent effect on nutrient intake in mildly obese women who are choosing food intake from a variety of foods.