Dietary Protein and Physical Training Effects on Body Composition and Performance

This chapter discusses the role protein and exercise play in the optimization of muscle mass and performance under normal conditions as well as during periods of acute and chronic muscle catabolism. Both the quality of protein and the quantity (dose) of protein can affect the rates of muscle protein synthesis (MPS) and muscle protein breakdown (MPB). While muscle mass is important, particularly in the context of aging, it is also important to consider the impact that dietary protein may have on improving muscle function. Several studies have examined the influence of chronic protein supplementation on changes in body composition and performance. The chapter also discusses the impact of protein supplementation on muscle function. Protein consumption during a resistance training (RT) program or a program of sport-specific training improves muscle performance. Consumption of protein increases MPS and decreases MPB and in a weight-stable individual results in maintenance of muscle mass over time.