Influence of dietary fat on postprandial glucose metabolism (exogenous andendogenous) using intrinsically C-13-enriched durum wheat

The present study evaluates the influence of different amounts of fat added to starch on postprandial glucose metabolism (exogenous and endogenous). N ine women (24 (SE 2) years old, BMI 20.4 (SE 0.7) kg/m(2)) ingested 1 week apart 75 g glucose equivalent of C-13-labelled starch in the form of pasta without (low fat; LF) or with 15 (medium fat; MF) or 40 (high fat; HF) g su nflower oil. During the 7 h following meal consumption, plasma glucose, non -esterified fatty acids, triacylglycerols (TG) and insulin concentrations, and endogenous (using [6,6-H-2(2)]glucose) and exogenous glucose turnover w ere determined. With MF and HF meals, a lower postprandial glucose peak was observed, but with a secondary recovery. A decrease in exogenous glucose a ppearance explained lower glycaemia in HF. At 4 h after the HF meal the ins ulin, insulin:glucose and postprandial blood TG were higher than those meas ured after the LF and MF meals. Despite higher insulinaemia, total glucose disappearance was similar and endogenous glucose production was suppressed less than after the LF and MF meals, suggesting insulin resistance. Thus, t he addition of a large amount of fat appears to be unfavourable to glucose metabolism because it leads to a feature of insulin resistance. On the cont rary, the MF meal did not have these adverse effects, but it was able to de crease the initial glycaemic peak.