Until recently, excess weight was generally overlooked as a major risk factor for chronic disease. Now a rapidly expanding body of data is deﬁning the impact of overweight and obesity on premature mortality, cardiovascular disease, type 2 diabetes mellitus, osteoarthritis, gallbladder disease, some types of cancer, and other conditions (Fig. 1) (1,2). Models using data from the Third National Health and Nutrition Examination Survey (NHANES III), the Framingham Heart Study, and other sources have demonstrated a direct, dosedependent relationship between increasing body mass index (BMI) and lifetime risk of various conditions (Table 1) (3-5). Data from the U.S. Behavioral Risk Factor Surveillance System indicate that obesity is associated with greater morbidity and poorer healthrelated quality of life than smoking or problem drinking (6), and a recent conservative estimate, derived from ﬁve long-term prospective cohort studies, suggests that overweight and obesity account for >280,000 deaths each year in the United States (7). The substantial morbidity and mortality associated with excess
weight underscore the pressing need to improve the education of health professionals and the public about the hazards of overweight and obesity and to remove the barriers to healthy eating and increased physical activity.