There are many food sources that deer transition to in the early Autumn. These Fall food sources include acorns, chestnuts, corn, and even pumpkins. A deer's diet will vary by region, but these are some of the most common foods they will eat in the Fall.
In the early Fall, whitetail deer start eating larger amounts of hard mast which consists of nuts that have lots of carbohydrates. This helps them put on extra fat to help them get through tough winters in the colder Northern climates.