Glucose and Insulin Response to High Carbohydrate Meals in Normal and Maturity-onset Diabetic Subjects

Previous studies using glucose tolerance testing demonstrated late afternoon glucose intolerance in normal subjects. To determine whether this alteration in carbohydrate metabolism also occurs with food intake, the effects of identical high carbohydrate meals on glucose tolerance were assessed in 12 normal and 5 maturity-onset diabetic subjects. A meal consisting of 60% carbohydrate, 14% protein, and 26% fat was administered for breakfast, lunch, and supper and the effects on glucose tolerance and plasma insulin concentration assessed. In normal subjects, glucose intolerance was observed during the evening meal, in association with a relative deficiency of plasma insulin secretion. In the maturity-onset diabetic subjects, glucose intolerance was observed at all meals but was exaggerated at supper. Thus, this study suggests that high carbohydrate diets composed primarily of simple sugars will result in exaggerated glucose intolerance in the late afternoon and should be avoided by maturity-onset diabetic patients.