Originally posted and full article at Research Frontiers blog:

You usually do not think much about teeth. You brush them twice a day and use them to chew your food. But who would have thought that the texture of your teeth can tell scientists, now or give or take a few million years, what you primarily ate?
A researcher at the University of Arkansas, Peter Ungar devised a technique called microwear texture analysis. He uses samples of dental molds from the Hadza people, modern hunter-gatherers in northern Tanzania, and compare the texture of those molds to samples of the human predecessors, hominins. If the technique is sensitive enough to discern between a meat-based diet and a tuber-based diet, he may be able to determine what hominins survived off of.