Physical activity in the management of obesity.

Physical activity is any movement of skeletal muscles that results in energy expenditure. Long-term success in weight management depends on both physical activity and dietary modification. Exercise has a pivotal role in weight management, optimising body composition by minimising fat-free mass losses and maximising fat mass loss; and, enhancing metabolic fitness. The amount and type of exercise needed to obtain health-related benefits may differ from that recommended for fitness benefits. Public health messages about exercise have focused on improvements in general health and fitness rather than on weight loss, prevention of weight gain or weight regain. About 2.5 times more exercise than the US Surgeon General's recommendation is needed to maintain energy balance and thus maintain a certain weight. The challenge is to get the exercise prescription right at an individual level.