A board certified internal medicine physician talks about why you should care about the level of apoB lipoproteins (fat transporters) in your blood. We follow the life cycle of an apoB fat transporter as it emerges from your liver as a VLDL (very low density lipoprotein), morphs into an IDL (intermediate density lipoprotein) and finally ends up as a cholesterol-rich LDL (low density lipoprotein). We see how all of these tiny lipoproteins can invade the walls of your arteries and cause disease.