The prevalence of childhood obesity in America brings even more attention to the issue of appropriate weight and height for teenagers. One in three children under the age of 18 in the United States is overweight or obese, according to the Centers for Disease Control and Prevention. Yet statistics and added focus on weight can be confusing for teenagers, who already may be feeling insecure about their developing bodies. Understanding what appropriate height and weight for teenagers means is important in ensuring good teen health.
Not just charts
Healthy height and weight for teenagers is based on more than just numbers on a chart. Everyone is an individual, and several factors must be evaluated to determine healthy numbers for each person. Age, height in relation to weight, body build and fat percentage need to be considered when determining the health status of anyone's body, including teens. For example, a muscular teenage boy with a large build may seem, by pure numbers, unhealthy by his placement on height and weight charts. However, muscle cells weigh more than fat cells. His weight and height alone are not enough to determine his overall fitness.
Body mass index
Because charts alone are not enough to determine health, the body mass index (BMI) is usually used to help quantify overall fitness. The formula for BMI is an individual's weight divided by his height squared.
However, teenagers and growing children are unique in that their BMIs will naturally--and healthily--fluctuate with developmental stages. Therefore, adult averages do not apply to teens. In general, paediatricians track the height, weight and BMIs of teens every two years between the ages of 11 and 24 to get a better idea of growth patterns, body build and overall health.
Charts are still important
Despite the fact that growth charts cannot be relied upon exclusively, they are still an important diagnostic tool. Charts work through percentiles, meaning they are comparisons of certain people in certain groups based on other people in that group. Because of this, there is some gauge of what is "normal," at least generally speaking. For a teen to be in the 50th percentile for weight means half of teens in that age and sex group will be taller and half will be shorter. The same goes for weight.
Height and weight charts are comparisons, but not exclusive determiners of what is healthy--partly because they can be misleading. For example, if one-third of all teens and children are overweight, that will drive up weight averages on the charts. Similarly, a person genetically prone to thinness may appear to be under healthy limits.
Hormones in puberty are part of what triggers the body to mature into adult form. Teens go through about two years of rapid growth. For girls, this usually occurs between the ages of 10 and 14; for boys it's usually between 12 and 16. Before this period, however, normal teen bodies may take on a little added weight. Girls also will increase body fat percentage during puberty, while boys typically lose it. During and right after this growth period, the body elongates--sometimes producing a stereotypically lanky teen body shape. However, everyone matures slightly differently. Paediatricians are generally most concerned with unhealthy eating and exercise habits, or height and weight that are at one extreme end of the chart.
Nutrition and exercise verses caloric intake
Paediatricians generally agree that nutrition is far more important than caloric intake for growing teens, but that caloric intake is part of nutrition. For example, a teen diet that has more than the recommended calories but consists mostly of fruits, vegetables, whole grains and lean protein is of less concern than a diet under the recommended caloric intake but full of junk food.
Similarly, moderate exercise is key to maintaining health. A teen who may be slightly overweight but has good nutrition, good caloric intake and a moderate exercise regimen may be of less concern than a teen who falls in the average zones in growth charts, but who does not maintain these healthy habits.