Although the title is a bit sensationalistic, an archeologist that studies food in the paleolithic era gave a TED talk and I think it is quite interesting - "Debunking the Paleo Diet" It should be noted, she isn't debunking any specific diet, she is debunking the idea that we can even come close to approximating a paleolithic diet.
The takeaways are the following:
1) All our current food is a result of agriculture including vegetables, fruits and nuts
2) Paleolithic man ate legumes and grains as early as 30,000 years ago
3) We should eat a variety of foods potentially including legumes and grains
4) We should try to eat seasonally (on some level)
5) We should focus on whole foods and heavily limit processed foods which tend to concentrate calories in an unnatural way
6) No one diet could be used to describe Paleolithic diet
Anyway, it is interesting and no matter what diet you are on, it may provide insight. And she does emphasize that paleolithic man did not have a single diet so I don't see all of us having the same diet.
Although I try to mix things up, I can find myself eating the same foods day after day and maybe I should make an effort to mix it up just a bit more.