My conclusion has been: nobody really knows anything about nutrition, so I'm going to eat what I damn well please. (They used to say that margarine was better than butter, but now they've concluded that "trans fat" is actually worse than ordinary saturated fat.) Summing up all the various advice, it all seems to come down to "eating is bad for you." (And data on caloric restriction seems to confirm this!)

Remember this scene from Woody Allen's movie Sleeper?

Dr. Melik: This morning for breakfast he requested something called "wheat germ, organic honey and tiger's milk."
Dr. Aragon: [chuckling] Oh, yes. Those are the charmed substances that some years ago were thought to contain life-preserving properties.
Dr. Melik: You mean there was no deep fat? No steak or cream pies or... hot fudge?
Dr. Aragon: Those were thought to be unhealthy... precisely the opposite of what we now know to be true.
Dr. Melik: Incredible.