About 50% to 55% of a teen athlete’s daily energy requirement should come from carbohydrates. A carbohydrate snack or a drink of juice right after a training session helps to replace the glycogen in muscles. Carbohydrates at the next meal will help to keep the muscles primed for training.| HealthyChildren.org
Protein is essential for growth, energy, and tissue repair. Athletic performance depends on muscle strength, and muscles are made of protein. Although athletes who are involved in strength and endurance training may need slightly more protein, it’s a mistake to think you can simply build up muscles by eating lots of protein. Exercise, not dietary protein, increases muscle mass.| HealthyChildren.org