Obesity may be thought of as a body weight that conveys significant risk for adverse health outcomes. In children, obesity is defined as a BMI at or above the 95th percentile for age and sex, based on population data from the 1970s (1,2). The prevalence of obesity has increased markedly in U.S. children and adolescents in the past 30 years. Obesity-related risk factors and diseases formerly seen only in adults are increasingly being recognized in obese adolescents and even younger children. Race and ethnicity are terms used to categorize populations on the basis of shared characteristics. Race has traditionally been used to categorize populations on the basis of shared biological characteristics such as genes, skin color, and other observable features. Ethnicity is used to categorize on the basis of cultural characteristics such as shared language, ancestry, religious traditions, dietary preferences, and history. Although ethnic groups can share a range of phenotypic characteristics due to their shared ancestry, the term is typically used to highlight cultural and social characteristics instead of biological ones (3). Both race and ethnicity are, in fact, social constructs. The assumption that race reflects only biological distinctions is inaccurate. Categories based on race account for only 3–7% of total human genetic diversity, are not reliably measured, and are not always biologically meaningful (3,4). Furthermore, both race and ethnicity are constantly evolving concepts, making the task of comparing groups or following the same group over time quite challenging. For instance, the increasing proportion of the U.S. population describing their race as “mixed” or “other,” as well as changes in ethnic self-identification across generations and occasionally even within the same generation, makes it difficult to assign individuals to invariant categories of race or ethnicity. Nevertheless, the social importance given to these constructs to describe …