FYI: if you've told your family about the paleo diet, some time this week you are liable to get sent this article Neanderthals may have feasted on meat and two veg diet by your Aunt Maude, who was dismayed last Thanksgiving when you didn't want two helpings of her refried bean casserole.
Since apparently reporters are unable to write the name of the paper or the journal in their lame articles, I went to the trouble of finding this paper, which is from the Proceedings of the National Academy of Sciences and is titled Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets (Shanidar III, Iraq; Spy I and II, Belgium).
While the method used in this paper represents considerable inguinity, the theory that Neanderthals ate plants has been around for quite some time. This evidence is more convincing than past evidence though, which focused mostly on the environments where neanderthals were thought to live, like this paper The Exploitation of Plant Resources by Neanderthals in Amud Cave (Israel): The Evidence from Phytolith Studies, which was published in 2004.
As usual, journalists didn't get the memo and have been portraying neanderthals as top level carnivores (they were in some regions) and have parroted the idea that they died out because they couldn't diversify their diet.
Michael, a commenter, pointed me to that paper and other commenters criticized it because it relied on plant remains in cave sediment, which could have been there for other reasons. True, but this paper is much more convincing because they looked at the actual teeth of neanderthals. Apparently these neanderthals had some dental plaque (it would be intersting to know if more northern populations had this) and in that dental plaque there were some teeny tiny fossils. And in those fossils they found evidence of particular plants consumed, as well as evidence that some of them had been cooked. So there were cooked plants in the mouths of these neanderthals. Which makes it likely that they were eating plants.
Some of the fossils identified were from date palms (tasty), water lily roots, flowering legumes, and grasses. Of course there could be errors in identifying these fossils and we can't know how many of these foods were eaten.
But as more and more of this evidence comes to light, the idea that a diet low in plant antinutrients = a paleo diet is going to be increasingly disputed.
Rough chart of this idea. Comments on additions/subtractions welcome.
The writer of what was formerly Plant Poisons and Other Rotten Stuff has been saying this for some time. I think it's wise to avoid the major neolithic agents of inflammation: gluten, sugar, and high omega-6 vegetable oils, but what you eat beyond that should be targeted towards your own constitution rather than what "Grok" ate.
Chris Kessler had a great post about that today which I suggest reading.