Clinical evaluation of the overweight patient.

Evaluation of an overweight patient is the first step in any therapeutic program. The syndromes of obesity can be classified in several ways. The first is an anatomic classification based on the size, number, and distribution of fat cells and fat tissue. The second is an etiologic classification based on identification of specific diseases and settings that produce obesity. Hypothalamic injury and endocrine disease such as Cushing's disease and the polycystic ovary syndrome are three identifiable causes of obesity. In this medicated society drugs are always candidates to produce weight gain. The most common causes, however, are stopping smoking, overconsumption of high-fat foods, a decrease in the level of activity, and aging. The natural history of obesity provides a useful framework in which to view both preventive and therapeutic strategies. Some individuals will never become overweight, but of those who do, about one-third will do so during the first two decades, and the remaining two-thirds will become overweight after age 20. A number of epidemiological and metabolic factors can serve as a guide to those individuals who are at high risk. Having overweight parents tops the list, but multiple births, cessation of smoking, and a sedentary lifestyle are additional factors. Therapeutic decisions should be based on risk-benefit decisions. The risk can be assessed from the body mass index, the distribution of fat in upper or lower body obesity, the rate of weight gain, and the degree of physical inactivity. After assessing risk, the therapeutic choices can be selected from the age category of the patient. With any therapeutic activity, involvement of the patient in a realistic approach to the treatment process is essential.