Corn, in its many incarnations, has been used as a food source for eons. When it comes to dried corn, you may be presented with the following four choices: cornmeal, corn flour, grits, and polenta. Here is a more detailed look at the differences between the fours and their uses. What Is Cornmeal? Cornmeal isn't complicated. Field corn is dried and then ground—that's it. So how does cornmeal differ from corn flour, grits, and polenta then?