TABLE 1
Recommended energy requirements, Kcal/day
|
Age, years
|
Male
|
Female
|
4–6
|
1800
|
1800
|
7–10
|
2000
|
2000
|
11–14
|
2500
|
2200
|
15–18
|
3000
|
2200
|
Adapted with permission from reference 1
|
Macronutrients
Macronutrients, such as carbohydrates, protein and fats, provide the fuel for physical activity and sports participation.
Carbohydrates
Carbohydrates are the most important fuel source for athletes because they provide the glucose used for energy. One gram of carbohydrate contains approximately four kilocalories of energy. Glucose is stored as glycogen in muscles and liver. Muscle glycogen is the most readily available energy source for working muscle and can be released more quickly than other energy sources.[1] Carbohydrates should comprise 45% to 65% of total caloric intake for four- to 18-year-olds.[1][7] Good sources of carbohydrates include whole grains, vegetables, fruits, milk and yogurt.
Protein
Proteins build and repair muscle, hair, nails and skin. For mild exercise and exercise of short duration, proteins do not act as a primary source of energy. However, as exercise duration increases, proteins help to maintain blood glucose through liver gluconeogenesis.[2] One gram of protein provides four kilocalories of energy. Protein should comprise approximately 10% to 30% of total energy intake for four- to 18-year-olds.[7] Good sources of protein include lean meat and poultry, fish, eggs, dairy products, beans and nuts, including peanuts.
Fats
Fat is necessary to absorb fat-soluble vitamins (A, D, E, K), to provide essential fatty acids, protect vital organs and provide insulation. Fat also provides the feeling of satiety. It is a calorie-dense source of energy (one gram provides nine kilocalories) but is more difficult to use. Fats should comprise 25% to 35% of total energy intake for four- to 18-year-olds.[7] Saturated fats should comprise no more than 10% of total energy intake.[1][3] Good sources of fat include lean meat and poultry, fish, nuts, seeds, dairy products, and olive and canola oils. Fat from chips, candy, fried foods and baked goods should be minimized.
Micronutrients
Although there are many vitamins and minerals required for good health, particular attention should be devoted to ensuring that athletes consume proper amounts of calcium, vitamin D and iron. Calcium is important for bone health, normal enzyme activity and muscle contraction. The daily recommended intake of calcium is 1000 mg/day for four- to eight- year-olds and 1300 mg/day for nine- to 18-year-olds.[7][8] Calcium is contained in a variety of foods and beverages, including milk, yogurt, cheese, broccoli, spinach and fortified grain products.
Vitamin D is necessary for bone health and is involved in the absorption and regulation of calcium. Current recommendations suggest 600 IU/day for four- to 18-year-olds.[8] Normal values of vitamin D also vary depending on geographical location and race. Athletes living in northern latitudes or who train indoors (eg, figure skaters, gymnasts, dancers) are more likely to be vitamin D deficient.[2] Sources of vitamin D include fortified foods, such as milk, and sun exposure. Dairy products other than milk, such as yogurt, do not contain vitamin D.
Iron is important for oxygen delivery to body tissues. During adolescence, more iron is required to support growth as well as increases in blood volume and lean muscle mass.[1] Boys and girls nine to 13 years of age should ingest 8 mg/day to avoid depletion of iron stores and iron-deficiency anemia.[7] Adolescents 14 to 18 years of age require more iron, up to 11 mg/day for males and 15 mg/day for females.[7] Iron depletion is common in athletes because of diets poor in meat, fish and poultry, or increased iron losses in urine, feces, sweat or menstrual blood.[2] Therefore, athletes, particularly female athletes, vegetarians and distance runners should be screened periodically for iron status.[2] Iron-rich foods include eggs, leafy green vegetables, fortified whole grains and lean meat.