Is it fat or cholesterol that clogs arteries?

It's several things: Atherosclerosis (hardening of the arteries) is a complex process. The majority of a plaque ("blockage") is made up of cholesterol and triglycerides that come packaged in ldl-cholesterol particles. Although we say ldl-cholesterol, there is triglyceride also. The plaque also contains many white blood cells which turn into immobile cells called foam cells. The plaque is an area of inflammation.

LDL, not Cholesterol: Neither: cholesterol: fat molecule manufactured by every animal cell, building block of each cell membrane (enables membrane fluidity/movement without tearing), is fundamental to the survival of every animal cell. Lipoproteins (proteins which transport all fats in the water outside cells) is the correct issue for artery disease (e.g. Ldl ≤700 nmol/l, HDL ≤45 µmol/l). Cholesterol ↓$, but misleading.

Chokesterol: Cholesterol is mostly made in the liver out of fat that you eat, saturated fat generally increases LDL cholesterol (bad cholesterol) more than other fats. Bad saturated fat is in red meat, butter, cheese, animal fat of any sort. Check out my website CardioGauge.com for heart health education. Good luck!