Maybe the Paleo Diet should include a nice warm bowl of oatmeal.

Strict followers of the fashionable “caveman” regimen shun starchy foods, sticking to breakfasts such as cold halibut with fruit and snacks of pork chops and celery. Bread, pasta, and potatoes are verboten. Our Stone-Age ancestors didn’t gorge themselves on grains and other starchy fare, the thinking goes, and neither should we.

But now evidence has emerged that people enjoyed their carbs even during the Paleolithic era, a period also known as the Old Stone Age that stretched from roughly 2.5 million to 12,000 years ago. A new analysis of a Paleolithic pestle shows it was dusted with oat starch, suggesting that ancient humans were grinding oats into flour and, presumably,