Colker, C. M., Swain, M. A., Fabrucini, B., & Kalman, D. S. (2000). Supplemental protein influencing body composition and strength in athletic adults. Medicine and Science in Sports and Exercise, 32(5), Supplement abstract 1661.

This study evaluated the effects of supplemental whey protein with or without added L-glutamine and branched-chain amino acids on body mass, body composition, lactate, and exercise performance over 10 weeks in resistance trained adults (N = 16). One group (G1) ingested 40 gm/d of whey protein and the other group (G2) consumed the same amount of whey plus 5 gm L-glutamine and 3 gm of branched chain amino acids (BCAAs). Each S was instructed to limit dietary protein intake to 1.6 gm/kg/day. Ss were evaluated before and at weeks 5 and 10 of the study. Ss participated in a supervised resistance exercise program. Exercise testing consisted of performing bench and leg press repetitions to failure.

In the first 5 weeks, G2 gained significantly in fat free mass and after 10 weeks in body mass when compared to G1. G2 improved significantly in bench press repetitions over 10 weeks. At both 5 and 10 weeks, blood lactate at four minutes post-testing in G2 was significantly reduced when compared to G1.

Implication. Whey protein, when combined with L-glutamine and branched chain amino acids, improves body composition and resistance exercise performance.

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