A typical paleo diet as depicted in a cave in Altamira, Spain. Photograph by Yvon Fruneau, licensed under the Creative Commons Attribution-ShareAlike 3.0 IGO license.

Dear Dr. Boli: This chocolate truffle cake says it’s “paleo friendly.” What does that mean? —Sincerely, A Shopper in the Packaged Desserts Section of Whole Foods.

Dear Sir or Madam: It means that this cake was not responsible for the extinction of the mastodon.

That was a little joke, of course. It really means that the food in question is suitable for the “paleo diet,” a dietary program in which the subject is supposed to limit food intake to those foods that were commonly available in paleolithic times, such as meat, root vegetables, nuts, fruits, and chocolate truffle cakes. There are strict FDA regulations for paleo friendliness, which require the manufacturer to certify that all materials used are more than 11,000 years old. If you observe the shelf tag, you will note that the price of “paleo friendly” foods generally reflects these requirements.