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Obesity has grown into a major public health issue over the past several decades. Since 1980, the incidence of overweight adolescents and children has tripled, while the prevalence of obesity in adults has doubled in the United States.1 The most recent data from the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2004 reveal that 66% of adults in the United States are overweight with 32% of these individuals meeting the criteria for obesity.2 Body mass index (BMI), defined as body weight (in kg) divided by height squared (in [meters]2), has become the most commonly used indicator of overweight and obesity. Overweight is defined by a BMI between 25 and 29.9 kg/m2. Adults with a BMI ≥30 kg/m2 are classified as obese, and those with a BMI ≥40 kg/m2 as morbidly obese (class III). Table 16-1 provides a chart that can be used to determine an adult's BMI and weight classification based on height and body weight. Children are at risk of being overweight if their BMI falls between the 85th to 95th percentile for their age and sex on standard growth charts, and considered obese at or above the 95th percentile.
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