A high protein diet is often recommended by bodybuilders and nutritionists to help efforts to build muscle and lose fat. It should not be confused with low-carbohydrate diets such as the Atkins Diet, which are not calorie-controlled and which often contain large amounts of fat.

While adequate protein is required for building skeletal muscle and various other tissues, there is ongoing debate regarding the use and necessity of high protein diets

in weight training and bodybuilding. Various sources advise people to consume anywhere from 0.6 to 1.5g of protein per pound of bodyweight per day (1.4–3.3g per kg). However, many medical professionals believe that consuming more protein than the Recommended Dietary Allowance provides no benefits, and that the excess is merely burnt for energy or excreted.

While there was initial suspicion that high protein diets increased the risk for renal failure, studies have shown that kidney problems only occur in people with pre-existing kidney disease. (Still, it should be noted that such problems may only become apparent when the stress of extra protein is applied to the kidneys.) Similarly, the long-held concern that it could worsen hepatic encephalopathy (brain disease due to malfunction of the liver) appears to be ungrounded.