Hi and welcome.
A lot fof us have found that by reducing our carb intake we lower our blood sugar and insulin response to food.
We also manage to lose weight. This then can also help to lower cholesterol (assuming that is what we need or want to do).
So we don;t have the side effects from diabetes because our blood sugars are out of the diabetic range and our bodies are not so likely to develop heart disease and furred arteries.
There have also been a huge amount of threads on the forum about cholesterol (that substance without which we would all be dead) and whether it is a good idea to control it using medication. I'll leave you to have a look around for some of them.
But to answer your specific point .. fats are not only good for us they keep us full for longer and providing they aren't from highly processed vegetable oil are pretty beneficial.
Thank you for your feedback, bulkbiker. There is contradictory advice out there, but most people seem to adopt a "find what works for you" approach, which is fair enough.