Overweight in childhood and adolescence.

The prevalence of overweight doubled among children 6 to 11 years of age and tripled among those 12 to 17 years of age between the second National Health and Nutrition Examination Survey, conducted between 1976 and 1980, and the most recent such survey, conducted in 1999 and 2000. Overweight in children and adolescents, defined as a body-mass index (the weight in kilograms divided by the square of the height in meters) at or above the 95th percentile for children of the same age and sex, is epidemic. Black and Mexican-American children and adolescents are disproportionately affected. Although only 25 to . . .