Many athletes, especially those on strength-training programs or who participate in power sports, are told that eating a ton of protein or taking protein supplements will help them gain muscle weight. However, the true secret to building muscle is training hard and consuming enough calories.

While some extra protein is needed to build muscle, most American diets provide more than enough protein. Between 1.0 and 1.5 grams of protein per kilogram body weight per day is sufficient if your calorie intake is adequate and you're eating a variety of foods. For a 150-pound athlete, that represents 68-102 grams of protein a day.