Diet composition and body composition in preschool children.

BACKGROUND In studies of adult humans and in animal models, dietary intakes of the macronutrients, particularly fat, are related to body composition; however, data on children are more scarce. OBJECTIVE We sought to determine whether diet composition is related to percentage body fat in children aged 1.5-4.5 y. DESIGN In 77 preschool children, a 4-d weighed-food record was used to determine intakes of total energy and energy from each macronutrient. An oxygen-18 dilution method was used to calculate percentage body fat. Habitual physical activity level was determined by calculating the ratio of total energy expenditure (from stable isotope analyses) to predicted basal metabolic rate. Dietary intake and body-composition data were analyzed to evaluate whether diet composition was related to body fat. Further analyses incorporating physical activity level were performed. RESULTS Percentage body fat was not significantly correlated with dietary intake variables (total energy or percentage of energy from fat, carbohydrate, or protein) and did not differ significantly among 3 increasing levels of each dietary intake variable by analysis of variance. In multiple regression analysis, physical activity level was related to body fat whereas diet composition was not. CONCLUSIONS We found no relations between dietary intakes of total energy, fat, carbohydrate, or protein and percentage body fat in children. The relation between fat intake and body fat may develop over time and may not be evident in preschool children. Energy expenditure, in particular physical activity level, may have a greater influence on body composition in early childhood.