Bread, if you'll excuse the pun, is engrained in Jewish life. Dark rye bread helps us through the work week, but come Shabbat, it's challah time. Rich as cake, challah holds the sweetness and blessing of shabbas. Like a caraway seed in the teeth, bread goes very deep.
Bread is wisdom.
Bread is also our way of telling time, not only from week to week, rye to challah, but also in yearly cycles. Some rabbis trace this fixation with bread to the Garden of Eden. Wheat, according to Rabbi Meir. Perhaps Rabbi Ze'era was growing a tall tale, but R. Meir understood, that bread symbolizes wisdom. The midrash associates Melchizedek with Jerusalem and his blessings with wisdom.