To compare the effects of postprandial hypertriglyceridemia and postprandial hyperglycemia on monocyte adhesion to endothelial cells, we investigated the effects of twice-daily standard diet (5% fat) and high-fat diet (30% fat) for 3 weeks on monocyte adhesion to endothelial cells and the expression of adhesion molecules in the aortic artery in non-obese type 2 diabetic Goto-Kakizaki rats. Fasting glucose, insulin, non-esterified fatty acid (NEFA), HbA1c, and body weight were comparable between the two diet groups. Postprandial glucose and insulin were higher in the standard diet group, while postprandial NEFA and triglyceride were higher in the high fat diet group, compared with the other group. The number of monocyte adherent to endothelial cells was higher in the high-fat diet group than the standard diet group. Consumption of high-fat diet resulted in overexpression of heme oxygenase-1, intercellular adhesion molecule-1 (ICAM-1), and connecting segment-1 fibronectin on the arterial wall, compared with standard diet. Thus, our data demonstrated that short-term intermittent high-fat diet prevented postprandial hyperglycemia in a model of type 2 diabetes without a significant increase in body weight. However, the resulting postprandial hypertriglyceridemia induces more monocyte adhesion to endothelial cells than postprandial hyperglycemia. This increased monocyte adhesion is associated with the increased aortic expression of adhesion molecules such as ICAM-1, and connecting segment-1 fibronectin.