As with any animals, the deer love foods that are easily found in the places they inhabit. One of their favorite foods is actually acorns. Not many other kinds of animals love the acorn, so the deer get most of the acorns to themselves. Well, as long as the squirrels don’t get them first. Deers also love fruit. They love, love, love fruit. Usually, they’ll eat whatever they can find in season, but they love fall fruits - like apples and persimmon. They’ll usually eat them after they have fallen to the ground. They can’t reach many branches on the trees.
One other thing deers like to eat is grass. It’s the same kind of concept as elephants: if they can’t find anything else, they eat what they walk through.