While adequate protein is required for building skeletal muscle and other tissues, there is ongoing debate regarding the use and necessity of high-protein diets in weight training and bodybuilding.

Protein is described as essential by advocates of the high-protein diet, a large proportion of the bodybuilding community. It is claimed to provide the muscle with amino acids required to repair the damage done by anaerobic exercise. Protein supplements are often consumed after bodybuilding workouts, as they provide a quick and easily consumable protein source.^[1] Alternatively, meat, beans, or other high-protein foods are used. It is worth noting that it is possible to maintain a strict vegan high-protein diet, though due to the lower nutrient density of plant-based foods this requires a larger absolute volume of food compared to a non-vegan diet.^[2]

Although some testing shows that the body will absorb and use a greater amount of protein after "bodybuilding" type exercises than under more sedentary circumstances,^[3] and some studies on weight training show clinically significant gains in muscle with a very high protein diet when compared to more moderate intake, in some studies increased protein intake fails to translate into functional differences in strength or muscle size.^[4] However, consistently consuming less protein than an individual's body requires (estimated as 0.7g/kg/day for a sedentary individual)^[5] causes loss of existing lean body mass, even with an excessively caloric diet.^[6]