I have a friend who is a naturopath and she recommends eating as much food as possible from what would be the traditional diet of your ancestors (which varies depending on where your people are from). For me that's things like bison, local giraffe, berries, squash, possibly corn and nuts (hard to know how far my ancestors wandered south). I do think that increasing the amount of locally sourced, unprocessed food makes my body feel better, but I am by no means adhearant to only eating an ancestral diet.
The thing I really think about this: our ancestors lived short, brutal lives. When they didn't die due to circumstance they typically still died young of disease, virus or other such cause. I'm happy I get to live beyond 40, and to get to keep a full mouth of teeth into old age. If you look at people of the Inuit of the far north, who still must depend predominantly on a traditional diet because food shipped that far north costs too much to make it accessable, you'll see a group of people who are free of some of the typical 21st century health issues, but people who have poor dental health and who don't live into old age.
When it comes to all those eating fads out there, I'm skeptical. We live in this world, in 2011. The world (and your heart) will not stop of you eat a Dorito now and then. People get so extremist about this shit (to the point where it looks a hell of a lot like disordered eating) when really it's just about not bullshitting yourself and eating and living responsibly.