During postprandial lipemia, dietary triglycerides transported by intestinal chylomicrons are hydrolyzed by lipoprotein lipase lining the vascular bed, with subsequent release of FFA for transport across the endothelium. Whether the intermittent flux of FFA has the same impact as the i.v. lipid infusion will be examined. Decreased endothelial function has been reported after a single or long-term dietary high fat load in normal subjects; however, others have found no effects on brachial artery vasoreactivity. Our preliminary studies indicate that high oral fat loads (60 g) resulted in higher FFA levels and BP changes, and reduced FMD compared to low fat load (25 g).