Epidemiology, risks and pathogenesis of obesity.

Obesity is operationally defined using a relationship of height and weight called the body mass index. Using this measure, more than 60% of Americans are overweight and over 30% are obese. To determine the importance of the body mass index, which would also label many athletes "overweight", we also need assessment of central fatness, and the medical conditions present in any given person. A problem of this magnitude is expensive, costing between 3% and 8% of health budgets in various countries. An increasing body weight increases the risk of early mortality, and enhances the risk of developing diabetes, gall bladder disease, high blood pressure, heart disease, osteoarthritis and certain forms of cancer. Although obesity results from an imbalance between what is eaten and what the body needs for its daily activities, these relationships are complex, and it is the "devil in the details" that is needed to provide clear public health strategies to prevent the progression of what some have called an epidemic.