In today's readings we hear John's account of the feeding of the five thousand. After the people eat of the five loaves and two fish, the leftovers, that which was "more than they could eat," fills twelve wicker baskets.
So what happens when Jesus feeds us? That is, what does the Eucharist do? First of all, in our celebration and reception of the Eucharist, the New Israel is constituted. Once we have been fed, twelve full baskets remain, the fullness of the re-creation of the twelve tribes of Israel. This puts us on the straight path to the New Jerusalem, the promised fulfillment of the world in Revelation 21.
Second, the leftovers are more than what he had when we started. That is to say that our mere humanity is fed by the Body of Christ and thus brought into the Sonship of the Word. We become what we receive, and are transformed into the Body of Christ. Humble bread and wine is received by humble humanity, and all together, by Christ's sacrifice, are brought into the the dynamic love which is the Trinitarian life. By the super-abundant goodness of God, we end up with infinitely more than we had at the beginning.
It was "more than they could eat." The mystery of the Eucharist is deeper than we can ever know.