Adequate protein intake is critical for stimulating muscle protein synthesis. Amino acids found in high-quality protein act as the building blocks for muscle protein synthesis and serve as chemical signals for stimulating protein metabolism. Activating protein synthesis is important for bodybuilders interested in increasing muscle mass and strength, and for older adults who progressively lose muscle mass as they age— a condition called sarcopenia.

Researchers from the University of Kentucky found that a single meal containing a moderate amount of protein (30 grams) stimulated protein synthesis as well as a meal containing 90 grams of protein. Also, dietary protein stimulated muscle protein synthesis equally in young and older people.

Consuming protein before or after a workout promotes protein synthesis. We can infer from this study that eating about 30 grams of high-quality protein maximizes protein synthesis. (Journal American Dietetics Association, 109: 1582-1586, 2009)