The following information is the diet protocol according to Mark Sisson's Primal Blueprint. You can find this information and more on his website Mark's Daily Apple.
Above is the new and improved "Primalized" food pyramid. Looks a bit different from what you're used to seeing isn't it? Missing is the over sized base of grains and starch. In it's place are fresh veggies and fruits. Cavemen were hunters AND gatherers. Protein from animals was a preferred food source but not always guaranteed. Animals were always on the move, looking for the next location with an abundance of food and water. Cavemen usually followed the herds, but varying conditions made the hunt difficult and often they went home empty handed. That is where surrounding vegetation came in handy. Cavemen foraged and consumed seasonal fruits, veggies, nuts and seeds along with (or sometimes place of) the varying types of meats.
So when you are trying to decide what to eat, ask yourself "is this something a caveman could find in the wild?" (or at least be able to create it using what is found in nature). Look at the label. Are there a bunch of ingredients listed that you can barely pronounce or have NO idea what they even are? If the answer is "yes", it is NOT primal!
But grains are found in nature, so why can't I eat them?
Mark Sisson talks about this in his "definitive guide to grains" article:
"We humans had the pleasure and occasional scourge of evolving within a hunter gatherer existence. We're talking some 150,00 plus years of hunting and foraging. On the daily scavenge menu: meats, nuts, leafy greens, regional veggies, some tubers and roots, the occasional berries or seasonal fruits and seeds that other animals hadn't decimated. We ate what nature (in our respective locales) served up. The more filling, the better. And then around 10,000 years ago, the tide turned. Our forefather and mothers were on the brink of ye olde Agricultural Revolution. But, as countless archaeological findings suggest, people became smaller and frailer as a result of this new agrarian, grain-fed existence. We developed the insulin response to help store excess nutrients and to take surplus (and potentially toxic) glucose out of the bloodstream. This was an adaptive trait. But it didn't evolve to handle the massive amounts of carbs we throw at it now. And yes, we're talking mostly about grains"
"Why You Got Fat" is a great video explaining the affects excess carbs and sugar have on our bodies:
Is it Primal?
You know the basics: Lean meats and veggies are healthy, grains and sugars should be avoided. But what about everything else?
For a long list of Primal foods check out the Smart Fuel category.