The Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine recommend 2.6 to 4.4 grams of protein per pound (1.2 to 2.0 grams per kilogram) of body weight per day for athletes, depending on training. In general, youth athletes need slightly more protein than inactive children. However, many studies show that kids typically get more than enough protein; even the kids who are "picky eaters."
Protein helps build and repair muscles, and most kids get plenty of it through a balanced diet. Protein-rich foods include fish, lean meat and poultry, dairy products, beans, nuts, and soy products. Too much protein can lead to dehydration and calcium loss.