Technical Abstract: Obese and diabetic patients may benefit from foodstuffs that are poorly absorbed and/or digested at a slower rate. Prowashonupana (PW) is a cultivar of barley, whose grains are enriched in beta-glucans, and thus may be less digestible than standard barley (barley cultivar (BZ) 594.35.e). To test this, both kinds of barley were grown in a chamber into which (13)CO(2) was injected. On two occasions, 10 healthy hydrogen (H(2))-producing adults consumed in random order one 35-g portion of each of the cooked, dehulled (13)C-enriched grains. CO(2) production was measured in a whole-body direct calorimeter, and H(2) and (13)CO(2) were measured in breath at baseline and intermittently for 450 min. The percentage of the (13)C dose recovered in breath was calculated. Results were compared by repeated measures analysis of variance (ANOVA). The percentage of the (13)C dose oxidized was greater after BZ than after PW consumption (P < 0.05). The area under the curve for H(2) was greater after PW (mean +/- SD, 8658 +/- 6582) than after BZ (5178 +/- 4759) intake (P < 0.05), whereas there was no difference in CO(2) production. We conclude that absorption of PW is significantly lower than that of BZ, making the modified barley appropriate for obese and diabetic patients.