Acute fuel selection in response to high-sucrose and high-starch meals in healthy men.

BACKGROUND

Despite considerable controversy over the inclusion of sucrose in the diets of people with diabetes, the acute metabolism of sucrose is not completely understood.

OBJECTIVE

Our objective was to investigate the metabolism of the monomeric constituents of sucrose after a high-sucrose meal.

DESIGN

Three test meals were consumed in a randomized, crossover design by 7 healthy male volunteers. Two of the meals were high in sucrose; one was supplemented with 200 mg uniformly labeled [13C]fructose and one was supplemented with 200 mg [13C]glucose. The other meal was high in starch, supplemented with 200 mg [13C]glucose. Fifty percent of energy was supplied as sucrose in the high-sucrose meals and as starch in the high-starch meal. Breath (13)CO(2) enrichment was measured at 15-min intervals and indirect calorimetry was performed for five 20-min sessions immediately before and during a 6-h postprandial period.

RESULTS

Carbohydrate oxidation rates rose much faster after the high-sucrose meals than after the high-starch meal. Breath (13)CO(2) enrichment rose faster and peaked earlier and at a higher value when [13C]fructose rather than [13C]glucose was given with the high-sucrose test meal. Values for breath (13)CO(2) enrichment from [13C]glucose after the high-starch meal were intermediate.

CONCLUSIONS

These results show that fructose is preferentially oxidized compared with glucose after a high-sucrose meal and that glucose is oxidized more slowly after a high-sucrose meal than after a high-starch meal.