Advances in diabetes for the millennium: nutritional therapy of type 2 diabetes.

Dietary modification is useful in both type 1 and type 2 diabetes. Glucose levels after a meal are largely determined by carbohydrate intake. Decreased intake of simple carbohydrates and increased fiber consumption lower postprandial glucose. Obesity has become epidemic in the United States and has dramatically increased the incidence of type 2 diabetes by augmenting insulin resistance. Dietary treatment of obesity has been frustrating. Success will require education in using foods with high fiber contents, low glycemic indexes, and low saturated fat levels. The use of natural foods must be supplemented by the use of semisynthetic foods with desirable properties. The educational efforts required are substantial and must be recognized by third-party reimbursement agencies. Operative procedures to decrease intake or reduce the absorption of food are being used with increasing frequency. Bariatric surgery is often successful in inducing a substantial loss of weight; however, this success must be balanced against the complications of surgery, which can be considerable. The pharmacologic approaches to treatment of obesity have focused primarily on anorexigenic agents. Several polypeptides that induce satiety are currently under study, including leptin and glucagon-like peptide-1 (GLP-1). Orlistat has been used to induce the malabsorption of fat to reduce caloric ingestion. Of the currently used oral hypoglycemics, metformin and the disaccharidase inhibitors have the best tendency to promote weight loss. There is active research on the uncoupling proteins that induce thermogenesis and promote the dissipation of calories. The beta-3 agonists act through the uncoupling proteins. The thiazolidinediones tend to promote weight gain through the PPAR gene locus. Agents that antagonize this effect could induce weight loss. The future will undoubtedly bring us drugs that are effective in causing weight loss. The advent of drugs to successfully combat obesity will substantially improve public health.