Acornerstone of diabetes treatment is attention to lifestyle. Unhealthy lifestyles, such as lack of physical activity and excessive eating, initiate and propagate the majority of type 2 diabetes. As discussed in previous articles in this series, the incidence and prevalence of obesity is rising quickly, both in the United States and in the rest of the world. The frequency of diabetes has risen in tandem with overweight and obesity in essentially all age-groups and ethnicities in the United States, and not by coincidence. Studies have thoroughly demonstrated strong relationships between excess weight and the risk of developing type 2 diabetes, hypertension, and hyperlipidemia. Physicians are frequently challenged with the task of motivating patients to lose weight and exercise to improve patients' diabetes control and slow or even reverse the natural course of the disease (Wang C, Harris WS, Chung M, Lichtenstein AH, Balk EM, Kupelnick B, Jordan HS, Lau J,2006). Lifestyle modification, although different, is an equally integral part of type 1 diabetes management. Patients with type 1 diabetes, because of their universal need for insulin, must learn to count or at least closely estimate the amount of carbohydrate they consume to help regulate their blood glucose levels and adjust their insulin doses. Failure to do so can lead to dangerous hyperglycemia or hypoglycemia (Hamet P, Abarca G, Lopez D, Hamet M, Bourque M, Peyronnard JM, Charron L, Larochelle P, 1982).
Discussion
It is difficult to overstate the importance of the relationship between lifestyle and the risk of developing type 2 diabetes. A recent study demonstrated that both women and men who have a BMI > 35 kg/m2 had a 20-fold increase in their risk of developing diabetes compared to people with a BMI of 18.5-24.9 kg/m2.3 Furthermore, prospective studies have demonstrated that lifestyle modification in the form of diet and regular moderate exercise sharply decreases the likelihood of developing type 2 diabetes in high-risk individuals who have impaired glucose tolerance or impaired fasting glucose (Haffner SM, Lehto S, Ronnemaa T, Pyorala K, Laakso M, 1998). The effectiveness of this intervention superseded that of metformin therapy.4 It is crucial, therefore, to properly educate obese patients and patients with glucose intolerance or impaired fasting glucose about the significance of exercise and weight loss in preventing diabetes, especially because many patients may make the presumption that medical therapy is the more important approach (Gougeon R, Styhler K, Morais JA, Jones PJ, Marliss EB, 2000).
Control of Existing Diabetes
Lifestyle interventions are not just beneficial before the development of diabetes. Several studies have clearly demonstrated the benefit of a healthful diet, regular exercise, and weight loss in individuals already diagnosed with diabetes. Substantial dietary restriction to 100 kcal/day has been shown to decrease fasting blood glucose of obese patients with diabetes and even in those without diabetes in as few as 4 days. This improvement was likely the result of decreased hepatic glucose output (Gougeon R, Pencharz PB, Sigal ...