The prevalence of obesity has increased markedly during recent years with the burden of obesity higher in minority groups in the United States. Rates of obesity vary according to age and employment, although the effect by socioeconomic strata is diminishing. Body mass index (BMI) and waist circumference (WC) are the primary anthropometric measures of obesity, but waist-to-height is increasingly being used as a measure that identifies both overweight and metabolic risk. BMI should be interpreted with caution in the elderly, children, and some Asian populations.