For me the Gospels clearly state something mystical is happening to the blessed bread and wine, it's more than a symbol. And our early church fathers confirm this view. Plus St. Paul implied this as well in his letter to the Corinthians:
> "The cup of blessing which we bless, is it not a participation in the blood of Christ? The bread which we break, is it not a participation in the body of Christ? Because there is one bread, we who are many are one body, for we all partake of the one bread." -1 Cor. 10:16-17
> "For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread, and when he had given thanks, he broke it, and said, 'This is my body which is for you. Do this in remembrance of me.' In the same way also the cup, after supper, saying, 'This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.' For as often as you eat this bread and drink the cup, you proclaim the Lord's death until he comes. Whoever, therefore, eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of profaning the body and blood of the Lord." -1 Cor. 11:23-27
St. Ignatius became the third bishop of Antioch, succeeding St. Evodius, who was the immediate successor of St. Peter. He heard St. John preach when he was a boy and knew St. Polycarp, Bishop of Smyrna.
"Do not err, my brethren: if anyone follow a schismatic, he will not inherit the Kingdom of God. If any man walk about with strange doctrine, he cannot lie down with the passion. Take care, then, to use one Eucharist, so that whatever you do, you do according to God: for there is one Flesh of our Lord Jesus Christ, and one cup in the union of His Blood; one altar, as there is one bishop with the presbytery and my fellow servants, the deacons. " -Epistle to the Philadelphians
http://www.therealpresence.org/eucharst/father/a5.html#ignatius
St. Justin Martyr, St. Clement (3rd Pope), St. Iranaeus say similar things, the Didache teaches it as well.
And St. Ignatius clearly argues against the gnostic heretics who deny the real presence.