Changes in Body Composition with Yogurt Consumption during Resistance Training in Women

Abstract

Resistance training is an effective method to decrease body fat (BF) and increase fat-free mass (FFM) and fat oxidation (FO). Dairy foods containing calcium and vitamin D might enhance these benefits. This study investigated the combined effects of habitual yogurt consumption and resistance training on body composition and metabolism. Untrained women (N = 35) participated in an 8-wk resistance-training program. The yogurt group (Y) consumed 3 servings of yogurt containing vitamin D per day, and the control groups maintained their baseline low-dairy-calcium diet. Postexercise, Y consumed 1 of the 3 servings/d fat-free yogurt, the protein group consumed an isocaloric product without calcium or vitamin D, and the carbohydrate group consumed an isocaloric product without protein. Strength, body composition, fasted resting metabolic rate (RMR) and FO, and serum 25-hydroxyvitamin D were measured before and after training. Calories (kcal x kg-1 x d-1) and protein (g x kg-1 x d-1) significantly increased from baseline for Y. FFM increased (main effect p = .002) and %BF decreased (main effect .02) for all groups with training, but Group x Time interactions were not observed. RMR and FO did not change with training for any group. Habitual consumption of yogurt during resistance training did not augment changes in body composition compared with a low-dairy diet. Y decreased %BF as a result of training, however, even with increased calorie consumption.