||In patients with diabetes, the benefits of tight glycemic control are unequivocal--delayed onset and progression of complications such as retinopathy, nephropathy, and neuropathy. However, intensive therapy with insulin and some oral antidiabetic agents come at the price of weight gain, a condition that can prevent attainment of tight glycemic goals and probably limits success of treatment. Insulin-related weight gain has been attributed to anabolic effects of insulin, appetite increases, and reduction of glycosuria. Use of metformin in combination with insulin is commonly recommended as a way to limit weight gain in patients with type 2 diabetes, and other new oral therapies and insulin analogs may also provide weight-control advantages. Lifestyle interventions (patient education about diet and exercise) promote weight loss in the short-term, but have not sustained weight control over long-term intervals. For lasting weight control, such interventions may need to continue throughout the course of treatment. Likewise, weight-loss agents, such as sibutramine and orlistat promote short-term weight loss, but no follow-up studies have yet demonstrated that this loss can be maintained for 5 years or longer. Bariatric surgery is the only treatment recognized to have lasting effects on weight control, but its use is limited at present to those who are morbidly obese.