Whey Protein Supplementation Results in Greater Gains in Lean Body Mass Compared to Soy Protein during a Progressive 9-month Resistance
Training Program
Brittanie M. Volk Medicine & Science in Sports & Exercise. 2012 44(5S): p 450
PURPOSE: Whey and soy are two quality protein sources used by athletes. Few studies have directly compared their ability to promote gains in lean body mass. We compared the effect of
daily supplementation with whey protein (WP) or soy protein (SP) on lean body mass responses to a 9-month progressive resistance training program
METHODS: Non-resistance trained men and women were randomized into a WP (n=19) or SP (n=22) group. The supplement provided ~22 g carbohydrate plus 21 g of either whey protein concentrate
or soy isolate. All subjects participated in a supervised, whole-body non-linear periodized resistance training program for 9 months (3x/wk). Body composition was assessed every 3 months via dual x-ray
energy absorptiometry (DXA).
RESULTS: Average daily protein intake, including the supplement, was 1.4 g/kg body weight. Despite consuming similar calories and protein during the intervention, gains in lean body mass
were significantly greater in the WP (3.3 ± 1.5 kg) than the SP (1.8 ± 1.6 kg) group. There were no significant differences in body mass and fat mass responses between groups.
CONCLUSION: Whey protein supplementation was more effective than soy protein in promoting gains in lean body mass in response to chronic resistance training.