We may not know much about it, but the doctor who invented bypass surgery and a partner did a study where they reversed everyone who changed their diets heart disease.

These were very sick heart disease patients who were told by their cardiologists they had a year to live, and Dr. Esselstyn (recommended in OPs blog post comments) and Dr. Farvalaro (the guy who invented bypass surgery) cured them all, then took photographic proof with an angioplasty.

Diet is the problem, and a proper diet can fix heart disease.