and that's simply your interpretation of John 6...it's NOT the consensus of the Church over a 2,000 year period...from the beginning...yours is a modern interpretation, because your protestant denomination is a modern one...
They took Christ at His Word, so why shouldn't we? If the Eucharist is merely a memorial and merely bread and wine, as your denomination preaches, then why does the Holy Apostle Paul warn us that:
"For he who eats and drinks in an unworthy manner eats and drinks judgment to himself, not discerning the Lord’s body. For this reason many are weak and sick among you, and many sleep." (1 Corinthians 11:29-30).
Would ordinary bread and wine make people sick or even cause them to die?
It is very clear from the writings of the early Church that, if the Church got it "wrong", they did so at a very early stage! The writings of St. Ignatius makes this very clear:
"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." (Letter to the Philadephians 3, 3-4) written around 110 AD.
And in his letter to the Smyrnaeans:
"From Eucharist and prayer they hold aloof, because they do not confess that the Eucharist is the Flesh of our Savior Jesus Christ, which suffered for our sins, and which the Father in His loving-kindness raised from the dead. And so, those who question the gift of God perish in their contentiousness. It would be better for them to have love, so as to share in the resurrection. It is proper, therefore, to avoid associating with such people and not to speak about them either in private or in public, but to study the Prophets attentively and, especially, the Gospel, in which the Passion is revealed to us and the Resurrection shown in its fulfillment. Shun division as the beginning of evil."
And St. Justin Martyr, writing in 150 AD tells us:
"We call this food Eucharist; and no one else is permitted to partake of it, except one who believes our teaching to be true and who has been washed in the washing which is for the remission of sins annd for regeneration, and is thereby living as Christ has enjoined. For not as common bread nor as common drink do we receive these; but since Jesus Christ our Savior was made incarnate by the word of God and had both flesh and blood for our salvation, so too, as we have been taught, the food which has been made into the Eucharist by the Eucharistic prayer set down by Him, and by the change of which our flesh and blood is nourished, is both the flesh and blood of that incarnated Jesus."
Keep in mind too G&P, there was NO "Roman Catholic Church" as we know it today, during 110AD and 150AD...there was nothing but the CHURCH...the One, Holy, Apostolic Church centered around Five (5) Patriarchates of Rome, Constantinople, Antioch, Jerusalem and Alexandria...therefore, this is no invention of the Roman Catholic Church...the Roman Catholic Church may have taken the doctrine and developed it more so than what it should've been, but the fact remains...the bread and actual wine, has always been viewed as the Body and Blood of Christ.
Therefore, from the first followers of our Lord Himself, through the Apostle Paul and the first leaders of the post Apostolic early Church, the Real Presence of our Lord can be seen to be an accepted teaching from the very beginning. It was only after the so-called "reformation" that any different teaching even existed! Martin Luther himself believed firmly in the Real Presence. It was not until the German Zwingli in 1519 that the idea that the Eucharist was merely a "memorial" appeared!