Are there certain foods that predispose you to developing corns?

No. There are no particular foods that one might eat that would cause the development of corns (eating corn doesn't cause corns!). However, if one had poorly-fitting shoes, and had to walk many miles every day to the market to buy food, then he might develop calluses and corns from his daily trips to get food.
No. Corns are formed from friction. Something rubs against a toe like a shoe or and adjacent toe.