Exercise and obesity.

Abstract

Exercise training in obese patients increases cardiorespiratory fitness, reduces cardiovascular disease risk factors, and increases caloric expenditure; however, significant exercise is required to induce changes in body composition in the absence of caloric restriction, particularly for people whose exercise capacity may initially be limited. Unless a large amount of lean tissue is lost by concomitant dietary restriction, it is unlikely that resting metabolism is altered by exercise, either long-term, or acutely after each workout. The thermic effect of food is negatively related to body fat content. Exercise prior to a meal improves the blunted thermic response to food in the obese but does not normalize it completely. It is noteworthy that physical activity is self-determined and is the only component of energy expenditure that is under volitional control. Exercise alone, without caloric restriction, is probably insufficient to yield significant fat loss except in individuals who are extremely motivated, whereas the combination of modest caloric restriction and physical training of different modes may be necessary to induce favorable changes in body composition.