A new analysis from the federal government shows the obesity epidemic among U.S. children and teens has hit a plateau.
It's good news because it means the obesity epidemic isn't increasing.
But a third of U.S. kids remain either overweight, obese or morbidly obese.
In the study, federal health officials figured out the body mass index (BMI) for over 8,000 children and adolescents. The BMI is a simple calculation of weight to height. It produces a number that rates individuals as normal weight, overweight, or obese.
The study found that 32 percent of children and teens are still at risk for diabetes, high blood pressure and all the other issues related to obesity, says study co-author Dr. Reginald Washington, a pediatric cardiologist at the the Rocky Mountain Hospital for Children in Denver.
Washington says that 20 years ago it was "almost unheard of" to see kids under age 10 having problems with type 2 diabetes. Now he increasingly sees such children and finds that he needs to treat them for elevations in cholesterol and take steps to reduce their hypertension.
It's not necessary to visit a hospital to see these children, he says. "Go to a local school, park out front and observe the kids and you will see that roughly one-third of them are overweight or obese. It's staggering."
Washington says that the best tool doctors have to identify overweight kids is the BMI.
A child may appear to be a healthy weight but a BMI calculation can prove otherwise.
Waiting until kids actually look overweight only makes losing weight more difficult, he says.
Measuring kids' BMI is slightly more complicated than measuring adults.
For adults, the BMI is an absolute number. If it's over 25, you're overweight.
With children and teens, weight fluctuates as they grow. So a child's BMI is compared with other children of the same age and gender.
BMI vs. Tape Measure
Washington says there's another tool that will likely become routine over the next five years — a simple tape measure.
In an editorial, Dr. David Ludwig, who runs an obesity clinic at Children's Hospital Boston, wrote that measuring a child's waist gives a more accurate prediction of disease risk than BMI.
"BMI is a very good screening tool but it doesn't tell us about body composition — the relative amounts of fat versus muscle," Ludwig told NPR. "At any given BMI, the risk for diabetes and heart disease can vary greatly according to physical activity level, diet or other factors including genetics."
For adults, studies show that abdominal fat increases the risk of cardiovascular disease.
Evidence suggests the same happens for children, which experts say is a good reason to closely monitor a child's weight as they grow.