When having your gun in your hands and selecting "eat" or "eat all" on a food it doesn't transition from putting the gun away to the character eating correctly.
Instead what happens is the character puts the gun on his back, but doesn't do anything with the food. When I go back into the inventory to select eat or eat all it says "you are already doing something". (when my character is doing nothing). I usually have to wait a couple seconds and then I can try it again and it will work.
I think it sorta fakes the command to eat without actually using the item or something.