Jesus says the flesh, including his, is useless for giving salvation only God saves so trying to eat him is a waste of time 

The Roman Catholic Church re-enacts the time when Jesus took bread and wine and said they were his body and blood and invited his apostles to eat and drink. This ceremony is called the Mass or Eucharist. Incredibly, the Church insists that the bread and wine are literally the body and blood of Jesus. The bread and wine at Mass turn into the real body and blood of Jesus. The Church says that the priest uses God’s power to change bread and wine into Jesus. He changes what makes the bread to be bread but without the bread seeming any different. So too with the wine. The priest raises the bread and wine at the heart of the Mass for adoration by the people.

This is supposed to be taught by God/Jesus in John 6 where Jesus said you must eat his flesh and drink his blood and you will go to Heaven forever to live with God.  Briefly, the text does not say bread and wine can become Jesus and there is a difference between saying that and saying Jesus is bread and drink.  Jesus met this question, "What shall we do that we may do the works God requires of us?" with "It is not works but work.  Believe in me whom he has sent."  John 6:28-29.  This stresses that orientating towards Jesus fulfills God's will not sacraments or masses.  They are not even required by God.

WHY THE WORDING?

Jesus said the bread was his body which would be given up for you.  Why not the more spiritual, "Take this and eat it.  This is my body which shall rise in you and make you whole"?  The hint is that the dead body of Jesus and the bread as a memorial of his death has no relevance to the resurrection faith.  The Church claims to be a resurrection people but that is not what its core rite the eucharist says. 

EXAMINATION

I would link John 6 to John 3:14-16 which says that as Moses lifted a snake in the desert to cure those who looked at it so Jesus will be lifted up so that everybody who looks in faith may have eternal life in him and he who believes will not perish but have eternal life.  Jesus does not mean he will be put up on a pole like the snake was so that simply looking when you are sick and dying cures you.  It shows we should not be so sure of the literal looking language that comes later in John 6.

Jesus upsets some of the disciples in John 6 by telling them they need to feed on the bread of life which is his flesh and if they drink his blood and eat his flesh they will have eternal life.  Catholics argue that it says you need to eat bread and drink wine that priests turn into the body and blood of Jesus.  They claim this miracle happens at Mass.

Some believe Jesus himself corrected those who thought like the Catholics did and do.

In John 6:63, Jesus said that his words which are spirit and life give life for the flesh is useless. Since he had been talking about the refusal of the Jews to believe in him, Catholics say he means that the flesh meaning the person who does not depend on grace or spirit is no good for holiness and union with God. They point out that he said flesh and not "My Flesh." Protestants say he means that flesh including his own flesh is useless and that it is the power and grace and spirituality it wins that saves. They reckon that that would be tantamount to a denial of the Catholic Eucharist. They are right because Jesus said the flesh after talking about his own flesh. Now he would have used a term perhaps “your flesh” if he had not meant his own. According to the rules of correct interpretation Jesus said his own flesh could not give life but only the spirit could.
 
It may be held that even Catholics believe that the flesh of Jesus is useless in itself. It is only the power of God in it that saves. If so, does it mean the verse does not disprove transubstantiation? No for Jesus would not talk as if he had meant the discourse symbolically. He said in the discourse that eating his flesh was necessary and now after he says the flesh is useless. He was not speaking to theologians but to ordinary men who would have understood from this that he was merely saying that what he said before was not to be taken literally. If the Catholics are right then he would have been clearer. He would have made sure we know that he did not intend to imply that the eating flesh was symbolism. He didn't do that so the Protestant interpretation is right. John 6 was written to prevent Christians attempting miracles like transubstantiation. Jesus had asked his hearers if they were insulted by his doctrine of eating flesh and drinking blood and then he says the flesh is useless. He is clearly trying to pacify them and tell them they got it all wrong – he meant you symbolically must eat his body and blood by accepting him as saviour for he will give his body and blood on the cross to forgive sins. It’s a spiritual eating and drinking. Availing of his sacrifice is eating and drinking him. That is all. It's symbolism.
 
The Holy Spirit is said to be water you can drink in John 7:37-39 and John 3:5 and nobody takes those literally.
 
Jesus says the words he gave were spirit and they were life (verse 6:63). Words are not literally spirit and life and never can be.  Jesus then is reminding us that this is heavy symbolism.  It hints that the stuff about eating him and drinking his blood is the same.  Here Jesus was illustrating that he doesn't mean to feed us literally with his body and blood. The words about feeding on Jesus and drinking his blood are said to be spirit and life. A message that gives spirit and life or salvation is a message that is strictly necessary for salvation. Even Catholics admit that the Eucharist in itself is not necessary for salvation. Jesus didn't have to give us the Eucharist.
 
To recap, the simplest interpretation must leave out the concept of transubstantiation. When he was talking about flesh after saying about his flesh it indicates that he was talking about his own body for to mean any other flesh in that context would be confusing and too oblique. To me the fact that there is no need for the flesh at all is sufficient proof that Jesus was saying that he did not mean his literal flesh would have to be literally eaten and so that he did not mean anything like transubstantiation.

Jesus before saying his words are spirit and life and the flesh is useless said, "“Do you take offence at this about eating my flesh and drinking my blood? Then what if you were to see the Son of man ascending where he was before?” 

He meant that if they saw him in his glory they would not be offended by his words. He is talking about their emotional good. He is not saying if they see him ascend to glory they will believe but if they see this they will cease to find his words revolting. Why? Because this vision would prove he is the Son of God who has come only with truth.

The word spirit means something abstract and non-material. It means something that is real but not in the way a material thing is real. Jesus said his words are spirit and life. Christians say he meant that you cannot believe him unless the Holy Spirit helps you. But the Church says that faith has to be a gift from God to save but you can develop belief without God’s input and his influence and that belief will not save. Jesus never mentions belief though in this bit! Read it. He says not that faithin his words is spirit and life but that his words are spirit and life. Words cannot be literally spirit and life. What are his words? The body and blood words and all that goes with them. Jesus is saying that the body is non-material food and the blood is non-material drink. He denies then that you really feed on his flesh and blood. You feed on his spriit and life and his grace.

* According to Catholics, if Jesus did not mean transubstantiation his disciples who heard his sermon would not have been upset to the degree that they went away and left him when he was finished talking about his flesh and blood being food and drink to them. But these disciples might have understood that Jesus was claiming to be the only way to God. John 6 clearly teaches that there is no salvation without Jesus. The doctrine seemed like egomania to them. They probably thought that he was saying that all Jews had been lost for not being followers of Jesus. The main thought in John 6 is that Jesus is the saviour and there is no salvation without him and the Eucharist itself can have no meaning without him being that.
 
* Jesus said that some can’t believe and wondered what they would do if they saw him ascend into Heaven. Some conclude that he must have taught a conversion of the Eucharist into his body and blood and that was what was so off-putting to those who went away upset vowing to have nothing more to do with Jesus. But that would only prove the conversion if he had already taught it and he certainly had not.

We conclude that Jesus said his words are life and spirit meaning feeding on his body and blood means eating and drinking his message and grace. He has the idea in mind that the gospel started with. Jesus was proclaimed to be the Word.  Jesus is grace and revelation in human flesh.