A surge in appetite around the age of ten in girls and twelve in boys foreshadows the growth spurt of puberty. How much of a surge? Let’s just say that Mom and Dad might want to oil the hinges on the refrigerator door and start stockpiling a small cache of their own favorite snacks underneath the bed.
“Adolescents seem like they’re hungry all the time,” says Mary Story, “especially boys.” Calories are the measurement used to express the energy delivered by food. The body demands more calories during early adolescence than at any other time of life. On average, boys require about two thousand eight hundred calories per day; and girls, two thousand two hundred calories per day. Typically, the ravenous hunger starts to wane once a child has stopped growing, though not always, says the dietitian. “Kids who are big and tall or who participate in physical activity will still need increased amounts of energy into late adolescence.” During middle and late adolescence, girls eat roughly 25 percent fewer calories per day than boys do; consequently, they are more likely to be deficient in vitamins and minerals.
The nutrients protein, carbohydrates and fats in food serve as the body’s energy sources. Each gram of protein and carbohydrate supplies four calories, or units of energy, whereas fat contributes more than twice as much: nine calories per gram.
Of the three nutrients, we’re least concerned about protein. Not because it isn’t important—50 percent of our body weight is made up of protein—but because “adolescents in the United States get twice as much protein as they need,” Story explains. The densest sources of protein include teenage favorites such as beef, chicken, turkey, pork, fish, eggs and cheese.
Carbohydrates, found in starches and sugars, get converted into the body’s main fuel: the simple sugar glucose. Not all carbs are created equal, however. In planning meals, we want to push complex-carbohydrate foods and go easy on simple carbohydrates. Complex carbs provide sustained energy; that’s why you often see marathon runners and other athletes downing big bowls of pasta before competing. As a bonus, many starches deliver fiber and assorted nutrients too. They are truly foods of substance: filling yet low in fat. Most nutritionists recommend that complex carbohydrates make up 50 to 60 percent of a teenager’s caloric intake. Simple carbs, on the other hand, seduce us with their sweet taste and a brief burst of energy but have little else to offer and should be minimized in the diet.
Nutrition experts recommend that fat make up no more than 30 percent of the diet. While Americans have trimmed their fat consumption in recent years, as a nation we’re still about 4 percentage points above the suggested level.
Let’s give dietary fat its due. Fat supplies energy and assists the body in absorbing the fat-soluble vitamins: A, D, E and K. But these benefits must be considered next to its many adverse effects on health. A teenager who indulges in a fat-heavy diet is going to put on weight, even if he’s active. It would take a workout befitting an Olympic athlete to burn off excess fat calories day after day.
Fatty foods contain cholesterol, a waxy substance that can clog an artery and eventually cause it to harden. The danger of atherosclerosis is that the blockage will affect one of the blood vessels leading to the heart or the brain, setting off a heart attack or a stroke. Although these life-threatening events usually don’t strike until later in adult life, the time to start practicing prevention is now, by reducing the amount of fat in your family’s diet. Researchers studying the eating habits of approximately two hundred California high school students were dismayed to find that more than one-third had abnormally high levels of blood cholesterol. Ultrasound scans of their carotid arteries revealed evidence of atherosclerosis already. The carotids, a pair of large vessels located in the neck, serve the brain. One of the doctors involved in the study commented that some of the teenagers’ arteries resembled those normally seen in a person twice their age. Fortunately, at this early stage, the condition is still reversible.
The Three Types of Fat
Dietary fat contains varying proportions of monounsaturated fat, polyunsaturated fat and saturated fat. The last type—found in meat and dairy products like beef, pork, lamb, butter, cheese, cream, egg yolks, coconut oil and palm oil—is the most cholesterolladen of the three. You want to limit your family’s intake of saturated fat to no more than 10 percent of your total daily calories.
The other 20 percent of daily calories from dietary fat should come equally from the two unsaturated kinds of fat, both of which are contained mainly in plant oils. Corn oil, safflower oil, sunflower oil, soybean oil, cottonseed oil and sesame-seed oil are predominantly polyunsaturated. So are the oils in fish and almonds. Foods high in monounsaturated fat, the healthiest kind, include olives and olive oil; peanuts, peanut oil and peanut butter; cashews; walnuts and walnut oils; and canola oil. You’ll want to avoid the partially hydrogenated oils in most margarines and vegetable shortenings.
If your family eats a lot of packaged and processed foods, you should make a habit of reading the “nutrition facts” food labels. You may be surprised to see how much fat, not to mention sugar and salt (sodium), is in the foods you eat every day. And almost all packaged goods that contain fat are likely to have partially hydrogenated fat, because it has a longer shelf life.
Vitamins and Minerals
A well-rounded diet based on the USDA guidelines should deliver sufficient amounts of all the essential vitamins and minerals. Adolescents tend to most often fall short of their daily quotas of calcium, iron and zinc. Unless blood tests and a pediatrician’s evaluation reveal a specific deficiency, it’s preferable to obtain nutrients from food instead of from dietary supplements, because unlike supplements vegetables, fruits and grains contain phytochemicals—natural substances that are believed to help safeguard us from disease.