Physical Activity and Obesity: Their Interaction and Implications for Disease Risk and the Role of Physical Activity in Healthy Weight Management

The prevalence of overweight and obesity is increasing at an epidemic rate. Increased adiposity, especially central or visceral adiposity, is predictive of cardiovascular disease/coronary heart disease, metabolic syndrome, and type 2 diabetes mellitus. The increased risk for cardiovascular disease/coronary heart disease and metabolic abnormalities associated with abdominal obesity may be mediated, at least in part, by increased systemic inflammation. Greater physical activity and/or fitness may reduce inflammation associated with greater visceral adiposity. Increased adiposity and low levels of physical activity and/or fitness are risk factors for atherosclerotic disease and type 2 diabetes, as well as the increased mortality associated with them. Increased physical activity/fitness reduces disease and mortality risk regardless of body mass index but does not completely abrogate the risks associated with obesity. Both moderate to vigorous physical activity and weight loss independently reduce the risk for type 2 diabetes and improve glucose/insulin metabolism via different mechanisms. Physical activity on the order of 2500 to 2800 kcal/wk may be necessary to prevent weight gain or maintain weight loss. Strength training is recommended as an adjunct to regular aerobic exercise but not as the primary mode of exercise for weight loss. Individuals are strongly encouraged to engage in regular physical activity because of the known health benefits, regardless of whether that activity results in weight loss.