Exercise is not an effective weight loss modality in women.
The excess caloric expenditure which results from physical activity should lead to weight loss if caloric expenditure at other times remains constant. Unfortunately, while there is good evidence for such an effect in men, there is little if any evidence for a similar effect in women. Weight loss with exercise does not readily occur in women unless accompanied by caloric restriction. Further, the role of exercise in maintaining resting metabolic rate while dieting has only marginal support. Potential reasons for the ineffectiveness of exercise in inducing weight loss in women include smaller body size and lower aerobic capacity, under-reporting of caloric intake, differences in body fat distribution and sensitivity to catecholamines, a different gonadal hormone milieu, and energy conservation resulting from evolutionary pressures. Nevertheless, regular exercise in women has many beneficial effects on lipids, glucose homeostasis and bone metabolism even if weight loss does not occur.