BACKGROUND: Glucose absorption from starchy food has only been described with small amounts ingested ( approximately 20-75 g). OBJECTIVE: Our aim was to describe total plasma (Ra) and exogenous glucose (Ra(exo)) appearance, glucose release from the liver (HGP), and the metabolic response after ingestion of 5 g polished or parboiled rice/kg body mass. DESIGN: Gas exchange and urea excretion were monitored in 8 healthy subjects before (3.5 h) and after (8 h) ingestion of rice intrinsically labeled with (13)C; [6,6-(2)H(2)]glucose was infused for the measurement of Ra, Ra(exo), and HGP. RESULTS: Changes in plasma glucose, insulin, lactate, and free fatty acids and the increase in Ra(exo) and Ra ( approximately 200%) and the decrease in HGP ( approximately 90%) were not significantly different (P > 0.05) after ingestion of either rice. Glucose oxidation was not significantly different (111.6 +/- 8.2 compared with 89.0 +/- 11.3 g; P = 0.13), but fat oxidation was significantly lower (9.9 +/- 1.7 compared with 21.3 +/- 4.0 g; P < 0.05) after parboiled than after polished rice. The percentage of the glucose load that appeared in the circulation over 8 h was not significantly different after ingestion of polished (70.4 +/- 4.5%) or parboiled (63.8 +/- 2.0%) rice (P > 0.05). CONCLUSION: Although the starch in parboiled rice is less susceptible to digestion in vitro, exogenous glucose availability was not significantly different after ingestion of large amounts of polished or parboiled rice. Glucose absorption remains incomplete 8 h after ingestion of both types of rice.