Multifactorial causation of obesity: implications for prevention.

Obesity threatens to become the foremost cause of chronic disease in the world. Being obese can induce multiple metabolic abnormalities that contribute to cardiovascular disease, diabetes mellitus, and other chronic disorders. Unfortunately, prevalence of obesity is increasing both in the United States and worldwide. Reasons for the rising prevalence include urbanization of the world's population, increased availability of food supplies, and reduction of physical activity. Although severe obesity has received much attention in the clinical setting, most obesity in the general public is only moderate. Even so, moderate obesity can elicit several metabolic abnormalities that are precursors to chronic disease. Therefore, for the population as a whole, moderate obesity is responsible for most obesity-related disorders. Moderate obesity is undoubtedly multifactorial in origin, and acquired influences probably exceed genetic factors in its causation. These acquired causes thus deserve greater attention in the development of a public health strategy for the control of overweight in the general population. A major public health effort is urgently needed to counter the increasing frequency of moderate obesity in the United States and throughout the world.