Emily, I think if you read it in context, you will find Jesus makes it pretty clear. Take a look at the entire conversation. The people have asked for a miraculous sign, mentioning that Moses gave them manna from God. Starting in verse 32, with Jesus' initial response, the Bible will be in bold italics and my comments will be like this.
Jesus said to them, "I tell you the truth, it is not Moses who have given you the bread from heaven, but it is my Father who gives you the true bread from heaven. For the bread of God is he who comes down from heaven and gives life to the world."
Not that this has anything to do with the matter under discussion here, but it is interesting that almost everything (and maybe everything) in the Old Testament is a physical picture of a spiritual truth in the New Testament!
"Sir," they said, "from now on give us this breas."
Then Jesus declared, "I am the bread of life. He who comes to me will never go hungry, and he who believes in me will never be thirsty."
Look at what He just said, for He presents the full truth right there, actually, and the rest becomes explanatory and, at one point, irritation, after that. GOING to Christ is the bread and BELIEVING in Him is the drink. He puts is simply, right from the first. But let's continue:
"But as I told you, you have seen me and still you do not believe."
Remember, these people were asking for a miracle. If you go back a bit in this chapter, you will find that He has just walked on water to the boat and that He and the disciples had then 'immediately' reached their destination on the other side of the lake. The people had evidence of a miracle right there. And THIS had followed the miraculous feeding of the 5000. What more do they want? This is why Jesus said that even though they have seen Him they did not believe. Not believing means they are not getting the drink, but are remaining spiritually thirsty.
"All that the Father gives me will come to me, and whoever comes to me I will never drive away. For I have come down from heaven not to do my will, but to do the will of him who sent me. And this is the will of him who sent me, that I shall lose none of all that he has given me, but raise them up at the last day. For my Father's will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise him up at the last day."
Everyone who looks to the Son and believes in Him will be given by the Father to the Son and will not be lost. There is NOTHING there about the bread and the drink, is there? That is because, as Jesus said, going to Him IS the bread and believing IS the drink, and thus those who look to Him, believing, get that spiritual food and drink, which is so superior to the manna or the fish that fed the 5000.
But look at the reaction of the Jews when He says that -- remember the Jews depended on the Law and on their ability to keep it...
At this the Jews began to grumble about him because he said, "I am the bread that came down from heaven." They said, "Is this not Jesus, the son of Joseph, whose father and other we know? How can he now say, 'I came down from heaven'?"
What follows from Jesus is typical Jewish, or Oriental, debate style. For another dose of it, go to John 3 where Jesus is talking to Nicodemus. Remember how Nicodemus asked 'how can a man enter his mother's womb a second time?' Nicodemus KNEW this was impossible, but he also understood that Jesus was using a physical picture to present a spiritual truth. Jesus knew Nicodemus knew this, and that this was their culture. So Jesus continued with Nicodemus just as He continues in John 6, returning to the physical picture to present a spiritual truth.
"Stop grumbling among yourselves," Jesus answered. "No one can come to me unless the Father who sent me draws him, and I will raise him up at the last day. It is written in the Prophets: 'They will all be taught by God.' Everyone who listens to the Father and learns from him comes to me."
That means, looking back at what He just finished saying a bit ago, that anyone who listens to God and learns from Him will have spiritual bread, i.e. come to Jesus.
"No one has seen the Father except the one who is from God; ony he has seen the Father."
Jesus is again lifting it out of the physical realm and into the spiritual realm. It is the Jews who are DELIBERATELY ignoring the form of the argument, which is theirs start to finish, and twisting it (as you will see) to avoid the meaning.
"I tell you the truth, he who believing as everlasting life. I am the bread of life. Your forefathers ate the manna in the desert, yet they died. But here is the bread that comes down from heaven, which a man may eat and not die."
Jesus is making a clear distinction here between the physical manna which provides physical life, and going to Him, which gives the bread that yields eternal life. He keeps trying to lift their eyes from the earth. Keep this in mind as you read the next part:
I am the living bread that came down from heaven. If anyone eats of this bread, he will live forever. This bread is my flesh, which I will give for the life of the world."
If we go to Christ, something else happens to us, which Paul explains in Romans 6:3-4 Or don't you know that all of us who were baptized into Christ Jesus were baptized nto his death? We were therefore buried with him through baptism into death in order that, just as Christ was raised from the dead through the glory of the Father, we to may life a new life.
Jesus had to die physically. When we become believers, we are baptized INTO HIS DEATH! (I doubt sincerely that is something the Roman Catholic church taught you!) Without that death, our life in Him would not be possible, for we, also, have to die -- but to ourselves. It is because of this forthcoming death that Jesus is, in the above, saying what He does, for when we go to Him, when we get that bread of life, we are baptized into His death, which was in the flesh. This is why He said, "This bread is my flesh, which I will give for the life of the world."
Now, remember the conversation with Nicodemus? Attitude is everything. Nicodemus came quietly and respectfully to Christ, asking questions. The Jews are doing neither here.
Then the Jews began to argue sharply among themselves, "How can this man give us his flesh to eat?"
They are doing the same thing Nicodemus did, but not for the same reason. Nicodemus continued the physical picture in order to learn more. The Jews are here taking the physical picture and using it argumentitively to discredit and challenge Christ. Thus, Christ's answer:
Jesus said to them, "I tell you the truth, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you. Whoever eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day. For my flesh is real food and my blood is real drink. Whoever eats my flesh and drinks my blood remains in me, and I in him. Just as the living Father sent me and I live because of the Father, so the one who feeds on me will live because of me. This is the bread that came down from heaven. Your forefathers ate manna and died, but he who feeds on this bread will live forever."
In the physical world, if you are actually eating the flesh and blood of an animal (or, ych, a human...) that means the animal or human is dead! Christ is saying that unless we participate in His DEATH we cannot live! What He is saying here has NOTHING to do with Holy Communion whatsoever. It has everything to do, instead, with being baptized, or immersed, into th death of Christ, for, remember, whoever loses his life for Christ will find it.
He says His flesh is real food and His blood real drink. And again He compares them with manna. They are so MUCH MORE real than the physical is what He is saying. I didn't start as early as verse 27 here, but here is something He had said just before that part that I started quoting: "Do not work for food that spoils, but for food that endures to eternal life, which the Son of Man will give you." Jesus is continually trying to lift them above the physical into a MORE real world, and, certainly, a more lasting one! The Roman Catholic church has mangled and destroyed the entire meaning of what Christ is teaching here.
He said this while teaching in the synagogue in Capernaum.
Whoa! He's not talking to the average Jew outside, but to the men in the synagogue. These men KNOW the Scriptures and the meaning of what is going on. Watch the reaction closely:
On hearing it, many of his disciples said, "This is a hard teaching. Who can accept it?"
They KNEW Jesus was not talking about cannibalism! They KNEW He was referring to death -- their own necessary deaths. How could they accept it? That most certainly IS a hard teaching! This is BEFORE the Cross, and they are not at all crazy about what they are hearing! Please note they never ask HOW they can eat His flesh or drink His blood. They are perfectly aware that He is not talking about a physical ingestion.
Aware that his disciples were grumbling about this, Jesus said to them, "Does this offend you? What if you see the Son of Man ascend to where he was before! The Spirit gives life; the flesh counts for nothing. The words I have spoken to you are spirit and they are life. Yet there are some of you who do not believe."
Here again Jesus denies the physicality of what He is referring to. The flesh counts for nothing. Is this not a contradiction?
The Greek word used for 'flesh' throughout this passage is sarx. It literally means meat stripped of the skin, but was also used to indicate natural or sinful man. Jesus had the only flesh uncorrupted by sin, so what we have is a play on words here. Flesh by itself counts for nothing. Spirit is what is important. And yet, because Jesus came in the flesh and died in the flesh, partaking of Jesus means partaking of His death, not His literal meat and blood. For He was only sacrificed once for all (1 Peter 3:18).
FAR from the idea of perpetuating Jesus' sacrifice -- for He is risen and sits at the right hand of the Father now -- we are to understand from His teaching and also from Paul's, that we must JOIN in His sacrifice and be killed ourselves, to ourselves. This is what partaking in His flesh and blood means, as He made very clear in this passage from John 6.