Effects of two experimental diets with a relatively high fat content--one enriched with saturated fatty acids (SAFA-diet) and the other with a low content of erucic acid rapeseed oil and rich in monounsaturated fatty acids (MUFA-diet)--on glucose and lipid metabolism were examined in healthy young women. The study was carried out with a randomized, crossover study design with each diet lasting 3 wk and a 2-wk washout period between the experimental diets. Glucose area under the curve during the intravenous glucose tolerance test (glucose dose 300 mg/kg, plasma samples before glucose dose and at 10-min intervals for 90 min) was significantly lower and the glucose disappearance rate after a glucose injection tended to be steeper after the MUFA-diet than after the SAFA-diet. After the MUFA-diet serum total cholesterol was 21.6% lower and serum low-density-lipoprotein cholesterol 29.5% lower than after the SAFA-diet, but high-density-lipoprotein cholesterol did not differ between the diets. The results give suggestive evidence that the dietary fatty acid composition affects glucose tolerance of healthy subjects.