Less than twenty-four hours before His death, Jesus took what appeared to be bread and wine and said "This is My body," and "This is My blood" (Mt 26:26, 28). The obvious response to these seemingly absurd statements is: "How can He give us His flesh to eat?" (Jn 6:52)
Yet, before we dismiss Jesus' words as those of a lunatic, we should remember that the Lord fed the entire Israelite nation for forty years by giving them manna, bread from heaven (Nm 11:7ff). The Lord can do anything!
Moreover, Jesus shows His lordship over nature by healing the sick (Mt 14:14), multiplying loaves and fish (Mt 14:17ff), walking on water (Mt 14:25), and especially by rising from the dead (see Rm 1:4).
How can we tell the almighty, risen Lord that He cannot change bread and wine into His body and blood? How can we tell God that He cannot do anything that would be "over our heads," just because it is beyond our human understanding?
Believe in miracles. Believe in the Eucharist. Believe Jesus is the risen Lord and God.