Reality check: childhood obesity can be treated. First, diagnose childhood obesity.

A new University of Michigan study of 2,060 adults found that only 13 percent of parents with an obese kid (ages 6-11) know it. 43 percent said the child was “about the right weight.”

Only 31 percent of parents with an obese adolescent (ages 12-17) know it. 56 percent said the kid was “slightly overweight.” Not.

Obese in kids and adolescents means a BMI higher than the 95th percentile for children who are the same age and gender.

Kids do not grow out of their obesity. Their risk of diabetes, metabolic syndrome, polycystic ovary syndrome, high blood pressure, cholesterol problems and schoolyard torture go way up.

4 out of 5 adolescents who are overweight grow up to be obese adults.

Know your BMI, free. Know your kid’s BMI, free. It could be life-changing.