This question was triggered by my watching the Australian ABC TV program Catalyst: The Heart of the Matter. Part 1. Dietary Villains that aired on 24th October 2013. The show claimed several things that went against what I believed to be a healthy diet to prevent heart disease. One of those claims was that blood cholesterol levels were pre-set for an individual and changing the diet would have no effect. At the time the show aired I was mid-stream through my own change of diet with dietary patterns as recommended on the Australian Heart Foundation website. Remarkably after ten weeks my total cholesterol level and LDL cholesterol levels had dropped remarkably. Thus, at least for me, that claim did not hold true. I decided to investigate whether there was any evidence in the literature of studies that had been done. I will link to any studies here.