Puberty marks the start of the teenage growth spurt and that time differs for each child. For girls, puberty typically begins at about age 12 or 13, about two years younger than for boys. From the school-age years through the teens, the average child grows to be 20 percent taller and 50 percent heavier. Body changes that happen as children mature are stressful for some and may affect their self-image and, perhaps, the choices they make about eating and physical activity. Some overweight children may start puberty sooner, but for now, there are too many unanswered questions to understand why.
All teens need enough calcium for bone growth and strength, protein for every body cell including muscles, carbohydrates and fats for energy, vitamins and minerals to carry through essential metabolic and brain functions, and enough water. Energy and nutrient needs increase to meet the growth demands of adolescence. Teens need understanding parents who appreciate that their adolescent's growth pattern, although different from a friend's, is perfectly normal.
How your teenage child grows — when, how and how much — has more to do with genes than with food choices. Smart eating will help determine if your teen will grow to have strong bones and a fit body.
Gender, body size, growth rate and activity level specifically determine how many calories teens need. Those involved in strenuous physical activity such as soccer, basketball, football or other sports may need 3,500 calories (more or less) daily.
Teenage boys on average need 1,800 to 2,600 calories a day if they're 11 to 13 years, and 2,200 to 3,200 calories a day if they're 14 to 18 years of age.
Teenage girls need more, too: 1,800 to 2,200 calories a day if they're ages 11 to 13, and 1,800 to 2,400 calories a day if they're ages 14 to 18.
Appetites correspond to growth spurts. Encourage teens to listen to their internal hunger and fullness cues, rather than external cues such as what their friends are eating or what the latest diet fad dictates.