Origen is unambiguous in his claim that this bread, for which we are to ask, does not refer to material food, but to spiritual sustenance (see passages below). In fact he suggests that it is this special nature of the 'bread' which required Matthew and Luke to coin this special word to describe it. Origen's 'spiritual' interpretation still finds a lot of support today.

Section from Origen's "On Prayer"

Give us today our Needful Bread, or as Luke has it, Give us daily our Needful Bread. Seeing that some suppose that it is meant that we should pray for material bread, their erroneous opinion deserves to be done away with and the truth about the needful bread set forth, in the following manner. We may put the question to them—how can it be that He, who says that heavenly and great things ought to be asked for as if, on their view, He has forgotten His teaching now enjoins the offering of intercession to the Father for an earthly and little thing, since neither is the bread which is assimilated into our flesh a heavenly thing nor is it asking a great thing to request it?  

........

And my Father, He says, gives you the true bread from heaven, for the bread of God is that which comes down from heaven and gives life to the world. It is true bread that nourishes the true man who is made in God’s image, and he that has been nourished by it also becomes in the Creator’s likeness. What is more nourishing to the soul than Word, or what more precious to the mind of him that is capable of receiving it than the Wisdom of God?