When you eat fat, it first shows up in the bloodstream as chylomicrons—lipoproteins that are triglyceride-rich. A lipoprotein is a particle that consists of some protein and some lipid like fat or cholesterol. [See illustration.]
When chylomicrons are broken down in the bloodstream, the triglycerides’ free fatty acids get deposited in fat or muscle cells and you’re left with particles that are cholesterol-rich. We call these remnant particles.
Remnants can promote plaque build-up in arteries. Like LDL, or low-density lipoproteins, the remnants can be taken up by scavenger cells and lead to the process we call hardening of the arteries.
Lipoproteins like LDL, HDL, and VLDL carry triglycerides (blue circles) and cholesterol (yellow circles) through the blood. As VLDLs shed their triglycerides, they become less dense and turn into artery-clogging LDL.