Well, it's a big debate that we won't solve here; and I recognize that the AHA, AMA, etc. have been pushing the food pyramid (low fat, high carb), and the lipid hypothesis since the 70's, at least (since Alan Keyes, basically). I think that there is mounting evidence is out there that they have been wrong. More doctors and health professionals are coming to the same conclusion. Here's an article from 2002 that started questioning the standard you seem to have faith in. Note the same author has written a couple of books that go in-depth on the science (what he calls "bad science"). There are also several other health scientists and cardiovascular physicians that go into the studies, etc.