As mentioned, it's obviously going to vary during the season. However, THE most attractive food source I've EVER seen anywhere, anytime in my region, is Soybeans when available. They will utilize beans from the minute they come up as fresh sprouts to the bitter cold late season when they search for the mature pods. When we leave soybeans standing throughout the season our deer will walk through all other corn and foodplots to get to standing beans. For this very reason I always make sure I have a bean source available for my local animals.
When I combine soybeans with corn.... it's THE best attracting food source I've found.