During the Consecration the bread and wine are changed, by God, into the Body and Blood of Our Lord Jesus Christ. While the appearances of the bread and wine remain when we receive the Eucharist we receive Jesus Christ Body, Blood, Soul, and Divinity. God wishes to share His life with us because He loves us even more than we love ourselves. That's why He died on the Cross for us and why each Mass is an unbloody re-presentation of His sacrifice on Calvary. He knows we need the strength the Eucharist gives us to stay faithful to His will.