Q. My child’s doctor said her BMI is too high, but she’s already an active kid!
A. BMI, or body mass index, is one way to assess weight by comparing it to a person’s height, but it’s not the final say. BMI is a calculation that divides weight in kilograms by height in meters, squared, and it’s usually a better gauge of health than weight alone. For example, picture two kids who weigh 50 pounds. Imagine that one is 4 feet tall while the other is 3 feet tall—adding height to the equation gives a much better picture of overall fitness. But while it’s important to compare weight and height versus simply looking at weight, it’s not clear what “too high” of a BMI is for kids. For adults, a BMI of 23 and above is thought to raise the risk of obesity-related diseases, but in children the story is much less clear and widely debated.—kids with higher muscle mass may have higher BMIs but in fact be quite healthy. Our society does need to focus more on healthy eating and exercise, but we shouldn’t over-focus on one measurement like BMI. If a clinical assessment determines that your child is indeed overweight, focus on her nutritional balance and aerobic fitness, and not just one number.
Lawrence D. Rosen, M.D., is the founder of the Whole Child Center in Oradell, New Jersey, one of the first green, integrative primary care practices in the U.S.
Have a question for Dr. Rosen? E-mail him at firstname.lastname@example.org.