There is a great deal of mis-reported and sensationalized research on diet, but this is probably the best article I've read on the subject of how the fats in your diet impact risk for heart disease.
http://www.strengthsensei.com/heart-...fats-straight/
The evidence comes down to the decrease of saturated fat intake and the increase in intakes of carbohydrates and poly-unsaturated fatty acids (PUFAs). Saturated fats (those found in animal fat, coconuts, butter ghee, etc) have traditionally been a majority of the calories in the human diet for centuries. Eating foods with saturated fats gives the body all the correct hormone signals as being full and energized, whereas eating carbohydrates encourages addiction, inflammation, and the production of fat and triglycerides in our blood which has a direct effect on the bad cholesterol (small, dense LDL, or pattern B) in our body, which increases risk of heart disease.
Simply put, get more of your calories from saturated fats and less from carbohydrates (grains, sugar, starch). Healthy diets get 50 - 70% of their calories from fats, believe it or not. It's easy to do this because fat is the most energy dense of all our food options.
As another poster mentioned, going to a registered dietician will simply get you a meal plan that is built around the Canada food guide, which is built around millions of dollars in lobbying and special interests, and not YOUR body. You will be consuming an inappropriately large amount of carbohydrates and an inappropriately small amount of saturated fats, which will make your problem worse.
Furthermore, you must understand why we have this in our bodies in the first place. Cholesterol is very important to our health and is critical to our well being. It is produced in the body naturally if you aren't getting it from your diet, it is that important. Cholesterol is used as the building block to several important hormones, including testosterone, among other things.
This is why exercise assists with managing cholesterol levels, because it trains the body how to deal with cortisol, the stress hormone. Excess cortisol impacts testosterone production. If you're not making testosterone, you're not using your cholesterol. In other words... train your body how to use the input for its purpose and you should see a reduction in the surplus. If not, you'll at least be getting closer to what the actual issue is.
Genetic predispositions are expressed through the hormone balance in our bodies, so it is important for us to understand and manage our hormone health ESPECIALLY if we have genetic predispositions for high risk conditions like heart disease. And there are so many factors that can impact your hormone health...
There is also good evidence that too much alcohol, a lack of magnesium, zinc and vitamin D impact testosterone production, which could be allowing for excessive accumulation of cholesterol.
See where I am going with this? I would suggest asking your doctor to connect you with an endocrinologist (hormone health specialist) to investigate if there are any other issues. Because cholesterol is a problem, I would be specifically interested in how healthy your testosterone levels are - and ask them to look at your results relative to your age group, not the bulk data. It's no use if you're at the bottom end of the range and you're about as healthy as an 80 year old man with diabetes!