Objectives: To assess differences in dietary intake of overweight/obese subjects and sex-, age-, and height-matched controls and to identify dietary components associated with increased deposition of body fat.
Design/subjects: A convenience sample of 52 overweight/obese and 52 normal-weight adults matched for sex, age (+/-1 year), and height (+/-1 inch) were recruited from the local area. Dietary intake was assessed with the Block 60-item food frequency questionnaire, physical activity was measured by the Yale Physical Activity Survey, and percent body fat was measured via dual-energy x-ray absorptiometry.
Statistical analyses performed: Independent t tests compared between-group consumption of dietary components. The ability of dietary components to predict percent body fat before and after controlling for age-, sex-, and physical activity-related energy expenditure and other macronutrients was assessed with multiple regression analyses. Spearman correlation coefficients examined relationships among nutrients, Food Guide Pyramid servings, and percent body fat.
Results: Overweight/obese subjects consumed more total fat, saturated fat, and cholesterol and less carbohydrate, complex carbohydrate, and dietary fiber than control subjects. Reported intake of dietary fiber was inversely related to percent body fat without (R(2)=0.052, P=0.02) and with (R(2)=0.045, P=0.013) control for potential confounding factors. Servings of fruit per day were negatively related to percent body fat (r=-0.40, P<0.01).
Conclusions: These findings suggest that the composition of a diet, especially low dietary fiber and fruit intake, plays a role in the etiology of obesity.