Effect of Added Fiber on the Glucose and Metabolic Response to a Mixed Meal in Normal and Diabetic Subjects

10 g of guar was added to a test meal given to 11 subjects, six of whom had insulin-dependent diabetes, after an overnight fast. The addition of guar to the meal produced an overall decrease in the blood glucose concentrations after the meal in both normal and diabetic subjects. The insulin secretory response in the normal subjects was less when guar was included in the meal than when it was not. In normal subjects, but not in diabetic subjects, the addition of guar also resulted in a diminished response of lactate, pyruvate, and alanine to the test meal and a blunting of the fall in serum ketones. This is likely related to the fact that the same dose of insulin was given in the diabetic subjects with both test meals. Thus, in the normal circumstances, the diminished glycemic response to the guar-containing meal resulted in diminished insulin secretion, which was not the case with the diabetic subjects.