SummaryThe effects of diet enriched soybean fiber on glucose and insulin curves were studied in non-insulin-dependent diabetic human subjects. Postprandial glucose levels following a meal tolerance test in which fiber was given in powder form were lower in all subjects irrespective of the form of fiber intake. Consumption of fiber-rich bread for 12 weeks significantly reduced glucose levels at 0, 30, and 60 min following a meal tolerance test in subjects with fasting blood glucose levels of 130 mg/dl and over. Each patient consumed, during a 12-week period, 40 g of fiber either in bread or as a powder suspended in milk. Following the consumption of fiber for 12 weeks, a reduction of plasma insulin was observed, but without a statistical significance. Body weight and plasma lipid levels did not change throughout the study period.