The acute effects of adding a large amount of wheat bran to a mixed meal was examined with the artificial pancreas in seven insulin-dependent diabetic patients. The timing of the peak blood glucose concentration and its magnitude were similar with both low- and high-wheat fiber meals. The total and net areas under the glucose curve were comparable. After adjusting for individual basal needs, the insulin requirements for the test meals were nearly identical. We observed no beneficial effect of added wheat bran from this study. We could not demonstrate any need for diabetic patients to adjust insulin dosage for occasional differences in meal wheat bran content.