Doctors already measure height and weight. But calculating the Body Mass Index (a proportion of your weight in kilograms divided by your height in meters, squared) gives your doctor a better idea of whether your kid is just a big girl, overweight, obese or may even need gastric bypass surgery.

95th percentile for age is obese; 85th-95th percentile means at risk for overweight and obesity, and should be treated–the risk for diabetes, heart disease and horrible teasing by other kids is real. 15% of kids between ages 6 and 19 are obese, and this fact is getting wide popular coverage, and personalized medical attention in private programs.

Body mass index is easy to calculate: you can do it here.. The American Academy of Pediatrics asks all pediatricians and family physicians to do just this. New policy was published in the peer-reviewed Journal Pediatrics. Read the whole policy here.