There are few high quality research studies that have examined the effects of resistance training with nutritional supplementation that have made detailed measures of muscle anabolism. A recent 10 wk resistance training study was conducted by researchers at Baylor University. The major aim was to compare the effects of supplementing with either protein or carbohydrate on several markers of muscle anabolism. Untrained men participated in a 10 wk resistance training program and either supplemented with 40 g of carbohydrate or 40 g of protein (14 g whey concentrate, 6 g whey isolate, 4 g milk protein isolate, 4 g calcium caseinate, and 12 g essential amino acids). Half of the respective supplements were consumed before and after the workouts. The results were overwhelmingly positive for the protein group. Despite similar background diets and identical training programs, supplementation with protein resulted in greater increases in several measures of muscle anabolism. Some of these markers included greater increases in fat free mass, thigh muscle mass, muscle strength, anabolic hormones, and muscle specific proteins. The results provide strong evidence that protein consumed before and after workouts augments muscle anabolism.
Willoughby DS, Stout JR, Wilborn CD. Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength. Amino Acids. 2006 Sep 20; [Epub ahead of print]