As far as I understand it, but I have no qualifications whatsoever, just done a lot of reading around - dietary fat is responsible for about 20% of our blood cholesterol. The liver makes the rest.
Some cholesterol is needed by our bodies. Your brain contains a lot of cholesterol, which it needs to function. The cholesterol in the fat under your skin turns sunlight into Vitamin D.
Too much carbohydrate in your diet can raise your cholesterol levels, particularly the triglycerides which are the real baddies. Saturated fats are supposed to be what raises your cholesterol, particularly processed fats such as those in shop-bought cakes, biscuits and ready-made foods, eg take-aways.
I eat only natural, unprocessed fats which don't seem to have too much affect on my cholesterol levels, but other people prefer to have a low fat intake.
Eggs used to be thought bad for cholesterol, but the advice on that has changed and you can now eat 1 or 2 per day without harm.
Hope that's helped a bit instead of totally confusing you! Someone who knows more than I do will be along soon to help.
Viv 8)