Effect of Digestible Carbohydrates on Glucose Control in Insulin-dependent Diabetic Patients

Recent studies have demonstrated that high-carbohydrate—high-fiber diets may improve the metabolic control in diabetes. To evaluate the influence of dietary carbohydrates separate from dietary fiber on blood glucose control, six insulin-dependent diabetic patients (IDD) were assigned in random order to two weight-maintaining diets for consecutive periods of 10 days. The diets differed in carbohydrate (41% in diet A and 60% in diet B) and fat content (41% and 20%, respectively) but were identical in calories, proteins, simple sugars, and fiber. After each dietary period blood glucose was continuously monitored for 24 h (Biostator GCIIS, Life Science Instruments, Miles Laboratories, Elkhart, Indiana). The M value was 48 ± 20 after diet A and 96 ± 27 after diet B (t = 3.83, P < 0.025); the mean daily blood glucose was 152 ± 5 mg/dl after diet A and 206 ± 11 mg/dl after diet B (t = 7.50, P < 0.001). Similarly, the blood glucose level for the 3-h period after each of the three main meals was lower after diet A than after diet B (analysis of variance: F = 5.2, P < 0.05). No significant difference in fasting serum cholesterol, triglycerides, or serum lipoprotein composition was observed between the two diets. In order to separate the influence of dietary carbohydrate and fat on postprandial blood glucose concentration, an additional test meal experiment was performed in eight insulin-dependent diabetic patients. In random order on consecutive days they were given two standard meals that were identical in carbohydrate and protein content and differed only in the amount of olive oil added to the meals (12 g versus 36 g) The average blood glucose increments calculated for the 3h after the meal were almost identical after the high-fat and the low-fat test meal. It is concluded that increasing the amount of dietary carbohydrate leads to the deteriorationof blood glucose control in ID