I wrote earlier this year about evidence that starch may have played a bigger role in Paleolithic diets than previously thought. A new paper adds to this discussion. Researches looked for starch granules on the dental calculus of ancient skeletons. For the skeletons they analyzed, almost every sample contained starch.
While this type of analysis doesn't say how much starch was in the diet, it does show it was prevalent across different ancient cultures. I really don't think that starch is the villian some have made it out to be. The focus should be on the quality of starchy foods - a quickly-digesting modern starch (like white bread) versus a slowly-digesting ancient starch (sweet potato). I just have a feeling that as more research is done, starch will turn out not to be as problematic as some think.