Exercise as treatment for obesity.

In recent times, affluent societies have become less physically active, and this has undoubtedly contributed to the increased incidence of obesity. Formal programs of exercise training can reduce body weight and fat, but, in many cases, the changes produced by exercise are small. When combined with energy restriction, exercise results in little further weight loss, but there is a strong trend for a greater loss of body fat. Thus, during diet-induced weight loss, added exercise seems to accelerate fat loss and maintain lean body mass, a condition which may prevent a decline in RMR. It is becoming increasingly clear that weight loss is better maintained when exercise is part of a weight-reducing program. Furthermore, following a period of diet-induced weight loss, participation in regular exercise amounting to an energy expenditure of more than 1500 kcal/week will result in more successful maintenance of the lesser weight. An emphasis should be placed on adopting life-long habits conducive to weight control and overall health rather than temporary measures for weight loss. A program which encompasses regular physical activity, modest energy intake, and reduced calories from fat has the potential to meet such a goal. Regular physical activity has the potential to reverse insulin resistance, improve cardiovascular function and the blood lipid profile, and control high blood pressure. Overweight individuals can obtain these important benefits even if body weight is not completely normalized during a program of regular physical activity. This should help alleviate problems of diabetes, heart disease, and hypertension often associated with being overweight. Further research is needed to identify more specifically the optimal amount, type, and intensity of exercise needed to produce weight loss or maintain ideal body weight. To date, the best recommendation comes from the American College of Sports Medicine. Persons are urged to engage in regular physical activity which promotes a daily energy expenditure of at least 300 kcal/day and to choose from a variety of activities, in particular, those which are enjoyable and that can be continued for life.