Prowashonupana (Prowash) is a shrunken-endosperm, short awn, waxy starch, hulless barley with low starch, high fiber, high protein, and a relatively high concentration of free sugars. The study was designed to compare equivalent breakfast meals (w/w) of Prowash and oatmeal for glycemic response in diabetic and non-diabetic subjects. A commercial liquid meal replacer (LMR) was included as a reference standard. A substantial reduction of the post-prandial glycemic peak following ingestion of Prowash was observed as compared to LMR or oatmeal. In the non-diabetic subjects, the maximal rise in glucose from baseline was 26.3 +/- 3.9 mg/dL after LMR, 41.3 +/- 3.9 mg/dL after oatmeal and 6.4 +/- 2.7 mg/dL after Prowash (p < 0.01). The maximal increase in glucose in the diabetic patients was 69.9 +/- 4.5 mg/dL after LMR, 80.8 +/- 8.8 mg/dL after oatmeal and 28.4 +/- 3.5 mg/dL after Prowash (p < 0.01). The maximal increase in insulin post-LMR was 33.9 +/- 3.6 mIU/ml in the diabetic patients and 54.0 +/- 9.8 mIU/ml in the non-diabetic controls. Oatmeal elicited a maximal insulin increase of 29.9 +/- 4.2 mIU/ml in the control subjects and 21.4 +/- 2.5 mIU/ml in the diabetic patients. In contrast, the maximal insulin increase after Prowash was 8.6 +/- 1.5 mIU/ml in the non-diabetic controls and 6.8 +/- 1.2 mIU/ml in the diabetic patients (p < 0.01).