When we think of cavemen and their eating habits, we usually imagine savage hunting and eating raw meat right off the bones. But the research conducted by the Oxford University shows that their diet was not what we assumed. Allegedly, the research proves that 3.5 million years ago cavemen used to eat edible grasses, nuts, fruits, but also insects and worms.
Now, this is obviously not a universal answer, giving the fact that there were cavemen in different parts of the world. Just like today, not every piece of land is the same, nor do we eat the same.
The data was collected during the study of fossilized teeth of the so-called "Australopithecus bahrelghazali." In their analysis, the researchers found that their diet consisted mainly of various plants.
Julia Lee-Thorp, a professor at Oxford University said that early hominis ate topical grasses and sedges, something apes didn't do (except the savannah baboon). She further explained that there is a possibility the cavemen ate animals that ate tropical grasses. The thing is, hominis were not carnivorous because they didn't have sharp teeth.
As you can see, there is still so much to be discovered, but we are one step further in understanding the lives of our ancestors. People are mostly interested in their eating habits because they want to incorporate those types of foods in their diet today. That is why paleo (short from Paleolithic) diet is so popular nowadays. Again, there is no certainty that going back to our roots is what a modern human needs, but it's sure popular.