Scope of the problem: Childhood obesity is a serious health problem in the United States.1 Data from the 2007-2008 National Health and Nutrition Examination Survey indicated approximately 17% of US children and adolescents (ages 2-19) years are obese.2Obesity prevalence increased from 5% to 10.4% (children aged 2-5 years); 6.5% to 19.6% (children aged 6-11 years); and 5% to 18.1% (adolescents aged 12-19 years) between 1976-1980 and 2007-2008.2 3 Some minority groups such as African Americans, Hispanic, and Native Americans, and low-income groups are at higher risk of obesity.4 5 However, the patterns are complicated, and not all low-income or minority groups are at high risk, and the relationship between obesity and social-economic status (SES) has changed over time in the US.4 6 Asian Americans have a lower prevalence of obesity than other ethnic groups, while higher income African American girls were more likely to be overweight than their lower income counterparts. The inverse relationship between obesity and SES is seen only in white females. However, SES factors only explain a very small portion of the variations in BMI (e.g., 1-2%).