Surely food in it’s purest form has been chewed and mixed with saliva. So it is still food essentially, it hasn’t been digested fully as in the stomach and in intestines, but has been broken down into what it really is. Essentially a ‘mush’ of edible substances that keeps us all going. Perhaps a portrait of certain dishes, photographs taken of the individual’s mouths with the food having been chewed. One step further would be to have the food separately on the table/plate, when it is chewed. When food is arranged on a plate, it is just a selection of objects arranged on a plate, yet once it has been chewed, it becomes useful and not wasted.
It is purely… food.