Optimal protein requirements and supplementation are a topic of great interest for competitive and recreational athletes. However, there is considerable debate as to what constitutes adequate intake in sporting populations. Multiple studies have been undertaken to assess protein utilization and protein supplementation. The current consensus in the literature advocates a diet containing 1.2-1.8 grams of protein per kilogram of body weight per day for strength athletes and 1.2-1.4 grams per kilogram of body weight per day for endurance athletes. Metabolic studies have shown a diet containing 2.4 grams per kilogram to be excessive. The average American diet contains more than 200% of the recommended dietary allowance (RDA), with some athletes consuming diets containing up to 6.4 grams per kilogram of body weight per day. Given a well-balanced, calorically appropriate diet, there is no evidence to support intake above these levels. Furthermore, female athletes in particular must take care to ensure that they receive adequate protein from a balanced diet and be selective about their athletic supplementation.