Obesity is a major public health problem. As reported by Ogden et al1 in this issue of JAMA, results of the 2003-2004 National Health and Nutrition Examination Survey (NHANES) indicate that an estimated 66% of US adults are overweight or obese, and 17% of US children are overweight. In the authors' analysis of NHANES data from 1999-2004, they found an increasing prevalence of overweight in children (ages 2-19 years) and an increasing prevalence of obesity in men, but not women; however, women had nearly double the rate of severe obesity compared with men. Excessive adiposity is a serious problem, and is associated with insulin resistance, dyslipidemia, low-grade inflammation, and changes in levels of growth factor and other hormones that play a role in the development of diabetes, atherosclerosis, and some types of cancer.2,3 Furthermore, evidence is accumulating that adiposity is associated with accelerated aging.2-4