In the story of the multiplication of the loaves, we are told that the people are hungry and have no food. Jesus takes the bread, blesses it (or gives thanks), and breaks it. This is the same action that Christ did at the Last Supper and which the priest does in the Mass at the words of consecration. The deeper reality of the Eucharist is that Christ takes the Heavenly bread of His Body, blesses it and breaks it in order so that it may be given to the faithful as spiritual food. The Body of Christ is life giving bread. It is the New Manna of which, if we eat, we will have everlasting life.
Christ performed this miracle (along with others) to point towards and prepare the Apostles for the Last Supper where He institutes the Sacrament of His Precious Body and Blood. The early Christians who read this account of the multiplication of loaves told by the Evangelists, would immediately recognize it as the Holy Eucharist and understand that Christ's giving of His Body and Blood fulfills our spiritual hunger, sustaining our souls and filling us with the very life of our Lord and Savior.