He might be, or he could be just fine. You can't tell by looking—even when he's yours. In a new survey, 49 percent of parents whose kids were overweight thought they were normal.
Even pediatricians miss weight problems, especially if they rely on just a look-see. "Visual diagnosis often means late diagnosis," says Nancy Krebs, M.D., cochair of the American Academy of Pediatrics Task Force on Obesity. For that reason, the AAP advises that at least once a year all kids age 2 and up have their body mass index (BMI) measured. BMI is a calculation based on height and weight, adjusted for age and gender, that's a good indicator of excess body fat. Yet only 11 percent of pediatricians check it routinely, and 3 percent never check it at all, says Dr. Krebs.
The earlier you find out that your child's weight may be going in the wrong direction, the easier it may be to make little changes (eating fruit and whole grains, not skipping breakfast, more active playtime, and fewer high-calorie snacks, for instance) that can reverse the trend. If he's 2 or older, ask to have your child's BMI measured at his next exam.