What Did He Mean?

Here's the statement Jesus made:

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. (John 6:53-56)

Here's how some of Jesus' disciples responded:

From this time many of his disciples turned back and no longer followed him. (John 6:66)

Here's how Jesus reacts to that:

You do not want to leave too, do you? (John 6:67)

And here is one disciple's reply (apparently speaking for others as well as himself):

Lord, to whom shall we go? You have the words of eternal life. We believe and know that you are the Holy One of God. (John 6:68-69)

Now here's the question I ask: What did Jesus mean when he said eat my flesh and drink my blood? If he didn't mean that literally, why were the disciples bothered by that? If they misunderstood Jesus (thinking he meant it literally when he didn't) then why don't we have record of Jesus saying something like, Wait, let me explain what I mean. Why did Jesus let them walk away?

I realize arguing from silence is, at best, tricky if not dangerous. But we do that with other passages of scripture - like the time Jesus tells the rich young ruler that he would have to sell everything he owned, give it all to the poor, then come and follow me. When the fellow hears that, he walks away quite sad. Why? Because he knew Jesus meant what he said literally. If he misunderstood Jesus, wouldn't we have record of Jesus trying to explain what he really wanted him to do? Or at least some commentary from the writer explaining what Jesus meant? (After all, that's exactly what we have when Jesus talked about tearing down "this temple" and he would rebuild it in three days - the gospel writer explains that Jesus wasn't talking about the human built temple but the temple of his body.)

Aaah... I know. Someone might say, "But he was speaking in hyperbole." We know Jesus used hyperbole as a teaching tool. He said, "If your right eye causes you to sin - gauge it out. If your right hand causes you to sin - cut it off." Well, maybe it was hyperbole... or maybe not. After all, is it really the eye or the hand that actually causes a person to sin? Or is it actually something else that is the "cause". Maybe this example really isn't hyperbole.

So back to my question. What did he mean about eating his flesh and drinking his blood... if he didn't mean it literally? I'm open to explanation...