Man: The Animal That Cooks

The great Byzantine mystagogue, St Nicholas Cabasilas, on why bread and wine are offered as Eucharist:

The ancients offered the first fruits of their crops, their flocks of sheep or cattle, or other goods. We set aside for God, as first fruits of our life, those gifts of human food, whose purpose is to sustain the life of our bodies; especially because life is not only maintained by food, but also symbolized by it. The Apostles said of Christ: "We ate and drank with Him after He rose from the dead" (Acts 10:41) to prove that they really saw him alive. And the Lord Himself ordered them to give the woman whom He had raised from the dead something to eat, in order to prove the presence of life by means of food. Therefore it is natural to consider food as the first fruit of life itself.

But you will say, perhaps, that all that was offered to God of old could be used as food by men; they offered fruit for which the farmers labored, and edible animals. Where these then first fruits of human life?

By no means: for none of these foods is proper to the human race, but nourishment shared by all creatures, fruits being the particular food of birds and grazing animals, while flesh is that of the carnivores. We call human that which belongs to man alone. Now the need of baking bread and making wine to drink is peculiar to man.

That is why we offer bread and wine.

Taken from A Commentary on the Divine Liturgy, 1:3.