Then the Jews began to argue sharply among themselves, “How can this man give us his flesh to eat?”
Don Carson writes, "Any dullard can see that Jesus was not speaking literally!"
Jesus is so explicit about this metaphor that these days we would call him a 'wind-up' merchant. Yet for those who have read the whole gospel, we remember that "The word became flesh." and the Greek word used there 'sarx' is the same word for flesh as is used in John 6 and not 'soma' as is used for the Eucharist "this is my body".