How is obesity defined for children aged 2-19 years?

Obesity in children aged 2-19 years is defined as a body mass index (BMI) that is at or above the 95th percentile for age and sex. This classification is based on growth charts developed by the Centers for Disease Control and Prevention (CDC), which take into account the normal variability in body composition among children and adolescents.

The use of percentiles allows for a more accurate assessment of a child's weight because it considers the child's growth relative to peers of the same age and sex. Being at the 95th percentile indicates that a child weighs more than 95% of children in the same demographic group, identifying them as having excess body weight that could pose health risks.

In contrast, a BMI at or above the 90th percentile indicates being overweight, and while a BMI of 30 or higher is a standard for adult obesity, it does not directly apply to children in the same way. A BMI above the 85th percentile indicates being at risk for overweight but does not meet the threshold for obesity, hence is less severe than the criteria of the 95th percentile.