Protein metabolic roles in treatment of obesity.

PURPOSE OF REVIEW: To understand the potential benefits of increased dietary protein during weight loss and the importance of distribution of high-quality protein at each meal. RECENT FINDINGS: Popular weight loss diets emphasize use of protein as a substitute for carbohydrates or fat to reduce insulin and minimize hunger and food cravings. These diets produce short-term weight loss, but long-term benefits remain obscured by failure to differentiate between outcomes of subject compliance and diet effectiveness. New molecular mechanisms have defined the benefits of protein as a meal threshold for the branched-chain amino acid leucine, which has been characterized as a unique signal regulator of muscle protein synthesis. Leucine consumed at 2.5 g triggers a postmeal anabolic response that protects metabolic active tissues during weight loss and increases loss of body fat. SUMMARY: Balanced daily distribution of protein with increased intake at breakfast and lunch protects metabolically active tissues including skeletal muscle during weight loss.