Body composition as affected by physical activity and nutrition.

Although exercise and/or training can augment maximum oxygen consumption, muscle strength, and endurance, it has not been shown to markedly increase lean body mass (LBM) or to markedly decrease body fat in humans unless androgens are given. Bed rest likewise leads to very modest changes in body composition. Over-nutrition, on the other hand, produces a significant increase in body LBM and fat, and undernutrition a fall in both; hence the evaluation of exercise programs should include assessment of energy intake.