Poppycock! Animal fats are what we have eaten over the entire evolution of the human body. We know how to process them. Some unsaturated fats have been in our diet over the millenia, bu tnot much. Vegetable oils are a new thing [proposed by "marketing" as being good for us - ie cheap to manufacture and easy to line their pockets] and our bodies haven't adapted to processing these properly, leading to stored fat and the obesity epidemic we are seeing right now...