EFFECTS OF VARYING CARBOHYDRATE CONTENT OF DIET IN PATIENTS WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS

Objective.-To study effects of variation in carbohydrate content of diet on glycemia and plasma lipoproteins in patients with non-insulin-dependent diabetes mellitus (NIDDM). Design.-A four-center randomized crossover trial. Setting.-Outpatient and inpatient evaluation in metabolic units. Patients.-Forty-two NIDDM patients receiving glipizide therapy. Interventions.-A high-carbohydrate diet containing 55% of the total energy as carbohydrates and 30% as fats was compared with a high-monounsaturated-fat diet containing 40% carbohydrates and 45% fats. The amounts of saturated fats, polyunsaturated fats, cholesterol, sucrose, and protein were similar. The study diets, prepared in metabolic kitchens, were provided as the sole nutrients to subjects for 6 weeks each. To assess longer-term effects, a subgroup of 21 patients continued the diet they received second for an additional 8 weeks. Main outcome Measures.-Fasting plasma glucose, insulin, lipoproteins, and glycosylated hemoglobin concentrations. Twenty-four-hour profiles of glucose, insulin, and triglyceride levels. Results.-The site of study as well as the diet order did not affect the results. Compared with the high-monounsaturated-fat diet, the high-carbohydrate diet increased fasting plasma triglyceride levels and very low-density lipoprotein cholesterol levels by 24% (P<.0001) and 23% (P=.0001), respectively, and increased daylong plasma triglyceride, glucose, and insulin values by 10% (P=.03), 12% (P<.0001), and 9% (P=.02), respectively. Plasma total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels remained unchanged. The effects of both diets on plasma glucose, insulin, and triglyceride levels persisted for 14 weeks. Conclusions.-ln NIDDM patients, high-carbohydrate diets compared with high-monounsaturated-fat diets caused persistent deterioration of glycemic control and accentuation of hyperinsulinemia, as well as increased plasma triglyceride and very-low-density lipoprotein cholesterol levels, which may not be desirable.