Adolescents experience a major growth spurt during puberty and thus require increased nutrient needs.
Boys experience the growth spurt at different times than girls.
For males, puberty usually begins anywhere from the ages of 12 to 15 years, with peak growth usually occuring at 14. For females, puberty occurs much earlier, between the ages of 10 and 13, with peak growth occuring around the ages of 12 to 13.
Because of hormonal insertions into the bloodstream, males develop greater muscle and skeletal growth, requiring more protein, iron, calcium, and zinc. Girls develop less muscle tissue and more fatty tissue, especially in the chest area in the form of breasts.
Thus, males need more nutrients than females during puberty, with the exception of iron. Girls need more iron because they are beginning to menstruate.
The recommended dietary allowances are based on real-world data associated with optimal health and serve as a guideline.
Iron requirements increase in adolescence because of the greater muscle mass and blood volume associated with the growth spurt. In addition, females require even greater iron because of the onset of menstruation. Iron is found in foods such as red meats, grains, and vegetables. Since iron in foods is not absorbed well by the body, an iron supplement may be required.
The increase in calcium requirements during adolescence is due to the increase in skeletal mass that occurs during puberty. The general rule for calcium is that the faster you grow, the more you need.
Extra protein will increase the muscle mass but, once the body’s protein needs are met, extra amounts are stored as fat, not muscle.
Calories are simply a way to measure energy. Calories are not nutrients. Some food have more calories than others. The specific number depends on the amount of carbohydrate, fat, and protein in the food—as well as the protein size.
Nutrient supplements are pills, powders, and liquids—not foods—that contain nutrients. For some people, these supplements are necessary.