Nobody is going to suffer extreme hunger while in a Disney park. With all the delicious snack and meal options around, it just isn't possible.
However, it is likely that you will occasionally crave a snack during an inopportune time. This might be when waiting in line for a ride, waiting for the parade to begin, or when the lines at the snack carts are just too long. By bringing a few granola bars or some other snack along, you can be prepared no matter when hunger strikes.