Whey protein and training with weights promote muscle growth

Wheyprotein in combination with weight training increases muscle growth. Australian scientists Alan Hayes and Paul Cribbs summarized the results of recent studies showing how whey protein and weight training work together to maximize gains in muscle mass and strength.
Amino acids contained in whey protein - especially leucine - serve as building blocks for muscle protein and stimulate genes that regulate protein synthesis and breakdown. Whey protein is rich in the branched-chain amino acids leucine, isoleucine and valine, which are crucial for maintaining a positive nitrogen balance, meaning that protein synthesis occurs at a higher rate than protein breakdown. Leucine is of particular importance as a signaling chemical for the regulation of protein synthesis, insulin sensitivity and energy expenditure. Leucine also increases the cycle rate of protein breakdown and protein synthesis. Branched-chain amino acids are crucial for the control of metabolism and energy expenditure. Training with weights generates muscle tension, which activates genes responsible for protein metabolism. Consumption of whey protein during and after exercise accelerates and optimizes protein synthesis.
(Current Opinion in Clinical Nutrition and Metabolic Care, 11: 40-44, 2008)