Polenta and grits are both made from ground corn, but they are different in terms of texture and preparation. Grits are typically made from hominy, which is a type of corn that has been treated with an alkali to remove the hull and germ. Polenta, on the other hand, is made from ground cornmeal. Grits have a finer texture and are usually boiled in water or milk, while polenta has a coarser texture and is often cooked with broth or other liquids.