Deer depend on a diverse community of microbes in their guts to efficiently digest the variety of foods they eat. Different microbes work on different types of food. Maintaining a diverse array of digestive microbes requires eating a diverse diet. That's why deer sample everything and how they ensure their digestive system can adapt to the seasonal variation in food availability. They are also known as "concentrate selectors", eating both grasses and forbs and high quality woody browse. Contrast this with elk, which are primarily grazers.
There science lesson over. Up to you to figure what they are eating in your neck of the woods, but given the variability what they eat and where it's found, concentrating on other life needs might be more "patternable." Travel corridors, water, bedding areas, rutting behaviors, etc. I rarely hunt "food sources" per SE although find the right oak at the right time and it's game on!