Changes in Terminology for Childhood Overweight and Obesity

A variety of different terms, metrics, and cut-off values have been used to describe and assess overweight and obesity in children (1–3). Strictly speaking, overweight refers to weight in excess of a weight standard, and obesity refers to excess body fatness. However, because body fat is difficult to measure, body weight is often used as a surrogate measure or indicator of obesity.
In children, weight varies with sex and age, not only with height (4,5). BMI calculated as weight in kilograms divided by height in meters squared can be used to express weight adjusted for height. To account for variability by sex and age, BMI in children is compared with sex-and age-specific reference values. In the United States, the 2000 CDC 2000 charts (6) serve as reference values. The CDC growth charts, issued in 2000, include smoothed percentiles of BMI-for-age in the United States population based on data from the 1960s and 1970s, with additional data from 1988–1994 for children under 6 years of age.