Long-term consumption of high-amylose starch on insulin and glucose response was investigated in 24 men: 10 control and 14 hyperinsulinemic (HI) subjects. Subjects consumed products made with standard (70% amylopectin, 30% amylose) or high-amylose (70% amylose, 30% amylopectin) cornstarch for two 14-wk periods in a crossover pattern. Starch products replaced usual starches in the self-selected diet for 10 wk followed by 4 wk of a controlled diet. After a starch-tolerance test with bread made from the starch consumed during that period, the insulin response curve area was significantly lower in all subjects after amylose consumption (P < 0.002). Glucose responses in HI and control subjects were similar and did not vary with the type of starch. Fasting triglyceride concentrations were significantly lower in subjects who consumed the high-amylose compared with the standard-starch diet throughout the study. Chronic consumption of high-amylose foods normalized the insulin response of hyperinsulinemic subjects and showed a potential benefit for diabetic subjects.