Picture table sugar – it’s granular and it has relatively rough edges. If you have too much sugar in your bloodstream over a period of time, those rough edges nick the walls of your blood vessels and cause damage.
Think of “bad” cholesterol (LDL) as a band-aid. It’s your body’s attempt to patch up the damage that the sugar has inflicted. The more extensive the damage, the more cholesterol you need to form an adequate band-aid. The cholesterol itself isn’t the problem, then – it’s actually trying to fix the problem. But with continued high intake of sugar, over time that band-aid plug gets bigger and bigger. Eventually it may impede blood flow, or the plug can become unstable and break off, traveling to some other part of the body until it encounters a blood vessel too small to accommodate it. Either one of these scenarios is bad.
Blood carries oxygen (among other things) to your tissues, and if not enough blood can get through to feed those tissues, it can cause serious problems. Most of the time when we talk about cardiovascular disease, we’re specifically talking about your heart, because your heart requires so much oxygen in order to do its job. Poor blood flow to the heart can have serious consequences. Ischemia is what happens with the heart muscle doesn’t get enough oxygen. Infarction (or heart attack) is what happens when blood flow is completely blocked.