The metabolism of the hydrogenated disaccharide maltitol was compared to that of sucrose in a group of eight normal subjects. On two separate days, with an interval of at least one week each subject ingested a load of 30 g of either substance. The evolution of the levels of plasma glucose, insulin, and free fatty acids was followed during the 6 hr following the oral load. Carbohydrate and lipid oxidation rates were assessed simultaneously by continuous indirect calorimetry during the 6 hr following the oral load. Plasma glucose and insulin peaks occurred 30 min after ingestion of the load for both sugars. The peak of the delta glucose concentration was significantly smaller after maltitol than after sucrose (21 +/- 4 vs 38 +/- 4 mg/100 ml, p less than 0.02), as was the peak of the delta insulin concentration (9.3 +/- 2.7 microU/ml after maltitol vs 25.5 +/- 5.0 microU/ml after sucrose, p less than 0.001). The peak of the stimulation of glucose oxidation occurred 60 min after the load of sucrose and 90 min after the load of maltitol. The delta glucose oxidation was significantly lower with maltitol than with sucrose during the first 90 min after the ingestion of the load. It was slightly higher (although not significantly) with maltitol than with sucrose starting from the 210th min. Maltitol resulted in a cumulated suprabasal glucose oxidation which amounted to 40% that obtained with sucrose after 180 min.