the relatively small number of very obese individuals, there are favorable long-term outcomes with gastric surgery (NIH, 1992). However, for the majority of obese individuals, there is currently no hope of a cure or spontaneous resolution, no expectation that the disease will stabilize, and no hope that the symptoms can be diminished. There are few diseases in which health-care providers can offer so little for those who struggle so much.
Another remarkable feature of obesity is that its victims suffer discrimination. Perhaps most lay persons, health-care providers, and even obese individuals themselves do not perceive the metabolic nature of the disease and thus view obesity as a problem of willful misconduct—eating too much and exercising too little (Stunkard and Sørensen, 1993). For example, a survey by Price et al. (1987) found that two-thirds of 318 responding family practice physicians believed their obese patients to lack self-control; 39 percent described them as "lazy," and 34 percent characterized them as "sad." Another study found third-year medical students to perceive very obese individuals as "unpleasant, worthless, and bad," even after direct contact with them in a psychiatry rotation over 8 weeks (Blumberg and Mellis, 1985). We believe strongly that it is important for the lay public and health-care providers alike to change the common misperception that the obese are largely responsible for their disorder and deserve to be discriminated against if they do not reduce to a more socially desirable weight.
In this chapter, we provide an overview of the problem of overweight and obesity in the United States, its incidence and prevalence, and the weight-loss practices of individuals. We then review current findings about the specific benefits of weight loss and summarize the tremendous personal and societal costs of obesity.
There is a surprising amount of variation in the terminology used to describe excess weight and in the definition of these terms (see box titled "Obesity and Its Measurement"). This variation leads to difficulties in estimating precisely the extent of these disorders and in trying to compare the results of different studies. Not only are the terms overweight and obesity often used interchangeably, there is considerable disagreement concerning how to identify those at increased risk from excess weight (Kuczmarski, 1992).
The problems involved in defining obesity are similar to those encountered in defining physical activity, hypertension, and hypercholesterolemia, in which continuous variables such as weight, blood pressure, energy expenditure, and blood cholesterol concentration are categorized