2.d. Fitness

Rationale: Nine RCTs testing the effects of weight loss on lipoproteins measured cardiorespiratory fitness, as measured by maximal oxygen uptake (369, 375, 380, 384, 399, 401, 404-406).  Weight loss was accompanied by increased fitness if the intervention included increased physical activity or physical activity combined with diet (375, 380, 401, 404-406).  These studies were not designed to test whether increased cardiorespiratory fitness reduces blood lipids independent of weight loss in overweight and obese adults. However, considerable evidence exists that aerobic exercise decreases triglycerides and total cholesterol and may increase HDL-cholesterol in men and women, particularly if accompanied by weight loss (411).