After puberty, the rate of physical growth slows down. Girls stop growing taller around age sixteen, while boys grow taller until ages eighteen to twenty. One of the psychological and emotional changes that occur during this life stage includes the desire for independence as adolescents develop individual identities apart from their families. As teenagers make more and more of their dietary decisions, parents or other caregivers and authority figures should guide them toward appropriate, nutritious choices. One way that teenagers assert their independence is by choosing what to eat. They have their own money to purchase food and eat more meals away from home. Older adolescents can also be curious and open to new ideas, including trying new food and experimenting with their diet. For example, teens will sometimes skip a main meal and snack instead. That is not necessarily problematic. Their choice of food is more important than the time or place.

However, too many poor choices can make young people nutritionally vulnerable. Teens should be discouraged from eating fast food, high fat and sugar content, or frequent convenience stores and using vending machines, which typically offer poor nutritional selections. Other challenges that teens may face include obesity and eating disorders. At this life stage, young people still need guidance from parents and other caregivers about nutrition-related matters. It can help explain to young people how healthy eating habits can support activities they enjoy, such as athletics, skateboarding, or dancing.

During puberty, growth and development during adolescence differ in males than in females. Both primary and secondary sex characteristics have fully developed, and the growth rate slows with the end of puberty. Fat assumes a more significant percentage of body weight in teenage girls, while teenage boys experience more substantial muscle and bone increases. Also, the motor functions of an older adolescent are comparable to those of an adult.

Energy and Macronutrients

Adolescents have increased appetites due to increased nutritional requirements. Nutrient needs are more significant in adolescence than at any other time in the life cycle, except during pregnancy. The energy requirements for ages fourteen to eighteen are 1,800 to 2,400 calories for girls and 2,000 to 3,200 calories for boys, depending on activity level. The extra energy required for physical development during the teenaged years should be obtained from foods that provide nutrients instead of “empty calories.” Also, teens who participate in sports must meet their increased energy needs.

Older adolescents are more responsible for their dietary choices than younger children, but parents and caregivers must ensure that teens continue to meet their nutrient needs. The AMDR is 45 to 65 percent of daily calories (203–293 grams for 1,800 daily calories) for carbohydrates. Adolescents require more grain servings than younger children and eat whole grains, such as wheat, oats, barley, and brown rice. The Institute of Medicine recommends higher protein intake for growth in adolescents. The AMDR for protein is 10 to 30 percent of daily calories (45–135 grams for 1,800 daily calories), and lean proteins, such as meat, poultry, fish, beans, nuts, and seeds, are excellent ways to meet those nutritional needs.

The AMDR for fat is 25 to 35 percent of daily calories (50–70 grams for 1,800 daily calories), and the AMDR for fiber is 25–34 grams per day, depending on daily calories and activity level. Young athletes and other physically active teens need to intake enough fluids because they are at a higher risk of becoming dehydrated.

Micronutrients

Micronutrient recommendations for adolescents are mostly the same as for adults. However, children this age need more minerals to promote bone growth (e.g., calcium and phosphorus, iron and zinc for girls). Again, vitamins and minerals should be obtained from food first, supplementing certain micronutrients only (iron).

The most important micronutrients for adolescents are calcium, vitamin D, vitamin A, and iron. Adequate calcium and vitamin D are essential for building bone mass. The recommendation for calcium is 1,300 milligrams for both boys and girls. Low-fat milk and cheeses are excellent sources of calcium and help young people avoid saturated fat and cholesterol. It can also help adolescents consume products fortified with calcium, such as breakfast cereals and orange juice. Iron supports the growth of muscle and lean body mass. Adolescent girls also need to ensure sufficient iron intake before menstruating. Girls ages twelve to eighteen require 15 milligrams of iron per day. Increased amounts of vitamin C from orange juice and other sources can aid in iron absorption. Also, adequate fruit and vegetable intake allow for meeting vitamin A needs.

Eating Disorders

Many teens struggle with an eating disorder, which can have a detrimental effect on diet and health. These disorders are more prevalent among adolescent girls but have increased among adolescent boys in recent years. Because eating disorders often lead to malnourishment, adolescents with an eating disorder are deprived of the crucial nutrients their still-growing bodies need. Eating disorders stem from stress, low self-esteem, and other psychological and emotional issues. Parents need to watch for signs and symptoms of these disorders, including sudden weight loss, lethargy, vomiting after meals, and the use of appetite suppressants. Eating disorders can lead to severe complications or be fatal if left untreated. Treatment includes cognitive, behavioral, and nutritional therapy.

Childhood and Adolescent Obesity

Children need adequate caloric intake for growth, and it is important not to impose very restrictive diets. However, exceeding caloric requirements regularly can lead to childhood obesity, which has become a significant problem in North America. Nearly one in three US children and adolescents are overweight or obese.

There are several reasons for this problem, including:

• larger portion sizes
• limited access to nutrient-rich foods
• increased access to fast foods and vending machines
• lack of breastfeeding support
• declining physical education programs in schools
• insufficient physical activity and a sedentary lifestyle
• media messages encouraging the consumption of unhealthy foods

Children who suffer from obesity are more likely to become overweight or obese adults. Obesity has a profound effect on self-esteem, energy, and activity level. It is a significant risk factor for many diseases later in life, including cardiovascular disease, Type 2 diabetes, stroke, hypertension, and certain cancers.

A percentile for body mass index (BMI) specific to age and sex determines if a child is overweight or obese. This is more appropriate than the BMI categories used for adults because children’s body composition varies as they develop and differs between boys and girls. If a child gains weight inappropriate to grow, parents and caregivers should limit energy-dense, nutrient-poor snack foods. It is also highly beneficial to increase a child’s physical activity and limit sedentary activities, such as watching television, playing video games, or surfing the Internet.

Programs to address childhood obesity can include behavior modification, exercise counseling, psychological support or therapy, family counseling, and family meal-planning advice. For most, the goal is not weight loss but instead allowing height to catch up with weight as the child grows. Rapid weight loss is not recommended for preteens or younger children due to the risk of deficiencies and stunted growth.

Avoiding Added Sugars

One major contributing factor to childhood obesity is the consumption of added sugars. Added sugars include sugar added to food at the table and ingredients in bread, cookies, cakes, pies, jams, and soft drinks. The added sugar in store-bought items may be white, brown sugar, high-fructose corn syrup, honey, malt syrup, maple syrup, molasses, anhydrous dextrose, crystal dextrose, and concentrated fruit juice. (Not included are sugars that occur naturally in foods, such as the lactose in milk or the fructose in fruits.) Besides, sugars are often “hidden” in items added to foods after preparation, such as ketchup, salad dressing, and other condiments. The primary offenders are processed and packaged foods, soda, and other beverages. These foods are not only high in sugar; they are also light in terms of nutrients and often take the place of healthier options.