Great question, one that might require some research on my part. Off the top of my head though, HDL/LDL/VLDL are lipoproteins, not fats. They are made in your liver, i believe and HDL is responsible for 'cleaning up' various crap floating around in your blood vessels and bringing it to the liver for disposal. LDL is the opposite, it tends to 'dump' crap in one's vascular system thats why the ratio and complete lipid profile is important, not just the total cholesterol. As far as what will tip the balance to favor one over the other, i would think that genetics play the predominant role.
I'll do some more research tonight, gotta dig through some books i have. First though its leg day and then i gotta take my girl out to dinner for our anniversary.