Do I trust the vegan doctors who say meat and dairy and oil causes heart disease? Or do I trust the ketogenic doctors who says that eating meat and dairy and oil does not cause heart disease?
I think both are right, but one has to be specific. What you posted above is too general.
Unprocessed, organic meat is surely healthy, in moderation. Processed deli meat is already proven to cause cancer due to the fake sodium and chemical preservatives. This goes for all other processed meats.
Raw dairy is VERY good for you. Processed dairy, from caged animals who are fed corn and grain (and not their natural diet of grass), is extremely unhealthy. What makes raw dairy healthy are the probiotics (which are destroyed when it is pasteurized) and also the calcium and vitamins that are in the milk but which ONLY come from the grass and healthy herbs that cows/chickens are supposed to eat naturally.
Oils are naturally present in vegetables and fruits and that's the best way for our body to get oils (outside of raw dairy or fish). But "plant oils" nowadays refers to all the processed oils used to preserve snack foods and also those "healthy" fats used to fry foods. This type of oil is very different from the natural omega oils present in spinach, kale, avacados or nuts.
I agree with you about gaining weight when eating fatty foods. Our body craves oily, starchy and "heavy" foods in the fall/winter because this is a way for us to put on weight for the winter and stay warm and also to add fat to our bloodstream, which also helps with staying warm.
In the warmer months, while we still need fat in our diet, we don't need a lot and we'll feel better if our diet is low in fat in the summer. We'll also be slimmer, which will help us be cooler. If we eat what is typically "in season" then we eat according to God's plan for food. And our body usually feels better.