Animal or non-animal based diet?

[Asolsutsesvyl]

There's four main types of fats:
- Polyunsaturated, the main fat in most vegetable oils. They oxidize easily, turning effectively rancid when heated, and are on that basis not suitable for use in frying things. Best served cold, stored in the dark.
- Monounsaturated, olive oil being a main example. A healthy fat to eat, but that "extra virgin" quality goes poof when you heat it to the frying point.
- Saturated, coconut oil being extreme, animal fats usually more mixed. The perfect fats for frying things in, as they don't go bad.
- Trans fats, made by "hardening" non-saturated fats into molecules different from those produced by organisms. Take the process further and you get plastic.

#3 and #4 are not the same. Trans fats are saturated, but natural saturated fats do not have the same molecular shapes.

Before the paradigm of saturated fat being dangerous became established, the main opposing view was that sugar is the culprit. That explanation remains popular in the LCHF crowd, either by itself or with the addition that it is the combination of sugar and saturated fat which causes the problem. I don't have any informed-enough view on atherosclerosis beyond pointing to those main ideas.