I'm with you on the paleo diet thing. For one thing, paleopeople lived far different lifestyles than we do today and wanted as much fat as they could get when they could get it. It might be a long time before another mastodon comes along. If I ate like a caveman, I'd be a lot more obese than I already am (although gorging on mastodon meat sounds pretty fun). For another, paleopeople were omnivores who, depending on where they lived and what was available, ate lots of different things.

Finally, what's so scientific about leaping to the conclusion that what one's ancestors ate was actually good for them or healthier than what is available today? They usually died before they were 30, for crying out loud!