Obesity

Obesity is not a disease that can be diagnosed on the basis of one or more blood tests or treated with one or a combination of medications. Until the true genetic contributions to the development of excessive fatness are better understood, treatment will remain a process of managing the balance between calorie in-take and expenditure. This behavioral treatment process must support reduction in calorie intake, modification of food selection, reduction in sedentary time, and increase in caloric expenditure. Important components of change include the use of diet diaries, to help recognize needed diet change, and the careful replacement of unhealthy food choices with lower calorie items that supply adequate amounts of protein, carbohydrates, minerals, and vitamins. Similarly, increasing energy expenditure can be the result of reducing reliance on cars, public transportation, elevators, and other conveniences, while increasing the time spent walking, bicycling, or other ways of expending energy, such as using stairs.

Modification of diet and activity and change in the degree of obesity among children over the age of eight years can occur in weekly group treatment programs that also involve parents in separate group sessions. Three treatment program characteristics contribute most to positive results: comprehensive treatment (including a combination of behavioral modification procedures, a special diet, and an exercise program); explicit inclusion of behavior modification techniques; and focus on children with more severe obesity. The diet should emphasize calorie and fat reduction (tailored to the child's age and metabolic needs), include a simple categorization of foods understood easily by children, and be supervised by a health professional.

More aggressive approaches to weight loss being used in the treatment of adults are under investigation in the treatment of adolescents, including the use of medications, very low calorie diets, and surgery. Until recently, the use of medications in the treatment of obesity has been of relatively little benefit. In the late 1990s, success with medications such as phentermine and fenfluramine, found to decrease appetite or increase satiety, was tempered by the discovery of unexpected and potentially fatal side effects. Two newer medications, sibutramine, an appetite suppressant, and orlistat, a blocker of fat absorption in the intestine, show promising results in adult treatment and are undergoing clinical trials for use in adolescents.

In more extreme situations, caloric intake can be reduced dramatically with the use of very low calorie diets and obesity surgery, but should be considered for adolescents only after completion of puberty. These diets include anywhere from 300 to 800 calories per day, primarily as protein and carbohydrate, and should be instituted only with adequate medical supervision, since severe nutrient deficiencies and medical complications, such as fatal rhythm disturbances of the heart, can accompany them. Surgical treatments either reduce the capacity of the stomach, thereby inducing earlier satiety, or they decrease the length of the bowel, thereby reducing the bowel's capacity to absorb fat from the meal. Significant side effects in terms of abdominal discomfort, diarrhea, and potential nutrient deficiency are common.

With the difficulty in treating obesity at any stage of life, attention is turning toward understanding the possible role of prevention. Efforts are underway to develop behavioral and biochemical approaches to prevention, particularly in children identified as high risk, based on their early growth patterns and family history.