Obesity is one of the most common, yet most puzzling, disorders of modern times. Cultural views of excess weight range from high regard to abhorrence. The prevalence of obesity within many societies has changed dramatically over time. Even within the United States, the prevalence of obesity varies widely among cultural and ethnic subgroups. The scientific community maintains that obesity is a complex phenomenon with multiple origins, yet the public view of the obese person is a rather simple one of a weak-willed individual who is gratified only by eating to excess.