Fluid milk consumed in conjunction with resistance training (RT) provides additional protein and calcium, which may enhance the effect of RT on body composition. However, the literature on this topic is inconsistent with limited data in adolescents. Therefore, we examined the effects of a supervised RT program (6 mo, 3 d/wk, 7 exercises, 40–85% 1-repetition maximum) with daily milk supplementation (24 oz/day, one 16-oz dose immediately post-RT) on weight, fat mass (FM), and fat-free mass (FFM) assessed via dual-energy X-ray absorptiometry (baseline, 3 mo, 6 mo) in a sample of middle-school students who were randomly assigned to 1 of 3 supplement groups: milk, isocaloric carbohydrate (100% fruit juice), or water (control). Thirty-nine boys and 69 girls (mean age = 13.6 yr, mean BMI percentile = 85th) completed the study: milk n = 36, juice n = 34, water n = 38. The results showed no significant differences between groups for change in body weight (milk = 3.4 ± 3.7 kg, juice = 4.2 ± 3.1 kg, water = 2.3 ± 2.9 kg), FM (milk = 1.1 ± 2.8 kg, juice = 1.6 ± 2.5 kg, water = 0.4 ± 3.6 kg), or FFM (milk = 2.2 ± 1.9 kg, juice = 2.7 ± 1.9 kg, water = 1.7 ± 2.9 kg) over 6 mo. FFM accounted for a high proportion of the increased weight (milk = 62%, juice = 64%, water = 74%). These results from a sample of predominantly overweight adolescents do not support the hypothesis that RT with milk supplementation enhances changes in body composition compared with RT alone.
Lambourne, Washburn, Lee, Betts, Gibson, and Donnelly are with the Div. of Internal Medicine, and Sullivan the Dept. of Dietetics and Nutrition, University of Kansas Medical Center, Kansas City, KS. Thomas is with the Div. of Clinical Nutrition, University of Kentucky, Lexington, KY. Smith is with the Dept. of Kinesiology and Health Education, Southern Illinois University Edwardsville, Edwardsville, IL.