DIET COMPOSITION RELATED TO BODY-FAT IN A MULTIVARIATE STUDY OF 203 MEN

Objective To assess whether usual diet (especially intake of dietary f at, carbohydrate, and fiber) was related to body fat percentage in hea lthy men. Design A written questionnaire provided data on demographic and lifestyle characteristics. Dietary fat, carbohydrate, protein, and fiber intakes were analyzed using the National Cancer Institute food frequency questionnaire. Percentage of body fat was determined using t hree-site skinfold measurements, and a submaximal treadmill test was u sed to estimate aerobic fitness. Subjects Subjects were 203 healthy me n (14.0+/-5.3% mean body fat) aged 21 to 71 years. The subjects were c hosen from randomly selected districts within Utah County and voluntee red for free diet and fitness evaluations. Statistical analysis Multip le regression analysis determined the extent to which the individual d iet components predicted body composition before and after controlling for energy intake, fitness level, body weight, and age. Multivariate analysis of variance was used to compare relative body fat groups in r egard to dietary variables. Results Reported intakes of carbohydrate ( P=.0085, R(2)=.022), complex carbohydrate (P=.0127, R(2)=.024), and fi ber (P=.002, R(2)=.03) were inversely associated with body fat after c ontrolling for age, energy intake, and fitness level. Energy intake wa s positively related to body fat after controlling for age, fitness le vel, and body weight. When subjects were separated into low-, moderate -, and high-body-fat groups, the fattest subjects reported eating sign ificantly more dietary fat (P=.05) and less carbohydrate (P=.01), comp lex carbohydrate (P=.01), and fiber (P=.005) than the leanest subjects . No significant difference in reported energy intake was noted across body fat groups. Applications Composition of the diet may play a role in obesity beyond energy intake in men over the long-term. Lifestyle changes for men should probably include modifications in diet composit ion, especially increased consumption of foods high in complex carbohy drate and fiber.