My Dear Sweet Friends,
The "Bread of Life" is that which produceth life and increase the life thereof. Because bread is food for the body of man, it follows that their is a "bread" for the spirit of man.
The spiritual bread is that which, as one eat thereof, one grow in spiritual. The wine and the meat art used in the same fashion. The reason that food stuff is used so much is because we all need to be fed, both the material and spiritual foods. The more one eat of the spiritual, the less one eat of the material.