Lifestyle Interventions and the Prevention and Treatment of Type 2 Diabetes

The diabetes epidemic is fueled by a societal increase in insulin resistance, caused by lifestyle factors, particularly excessive caloric intake and physical inactivity. Aging also plays a role in the increase in insulin resistance; however, even in older populations, the increase in insulin resistance appears to be attributable mainly to age-related obesity and inactivity. Insulin resistance reflects deposition of visceral, hepatic, and intramyocellular fat, while toxic messages from the adipose organ (free fatty acids, cytokines, and oxidative stress) impair insulin action to restrain glucose production in the liver and promote glucose disposal in muscle. Unexercised muscle is also insulin resistant because of intracellular sequestration of glucose transporters. These processes lead to hyperglycemia if compensatory secretion of insulin is inadequate due to decreases in pancreatic beta-cell function and mass, ultimately resulting in the development of prediabetes and, later, type 2 diabetes mellitus (T2DM). Lifestyle interventions, programs that promote diabetes risk reduction and weight loss through behavior change, increased physical activity, and dietary modification, can decrease insulin resistance and prevent or delay the development of prediabetes and progression to T2DM. Lifestyle interventions are also important to improve diabetes management, particularly early in the natural history before loss of beta-cell function and mass is so extensive that multidrug pharmacologic therapy is required. Effective interventions often include both an increase in physical activity (ideally, at least 150 minutes per week of moderate-to-vigorous aerobic exercise and strength training) and dietary modification to promote weight loss.