I think the problem is that people are getting the wrong kind of fat - mostly animal product fat. This is generally saturated fat, whereas the body needs unsaturated fat to utilize it properly, otherwise the person just puts on weight and gets clogged arteries etc. Nuts, I think, are the best source of fat as they are the right fat and very high in it, but obvious not good for those with a copper or allergy to nuts. Walnuts are also rich in omega 3's. But we live in a society that promotes animal products as wonder foods, so the benefits of other kinds of food are overlooked. A person might be told to go easy on the nuts, but eat a lot of meat, for example.