They seek out every little nook and cranny of your words for contradictions and impossibilities. It's frustrating to go through the stage in a teenager's life when everything I say is subject to the refiner's fire of a teenage mind. Jesus, I'm sure, could have used the same advice to the ones who listened to his words that day and so misunderstood his meaning. Jesus begins a perfectly nice conversation about being the living bread that came down from heaven and that whoever eats this bread will live forever. Jesus wants to be inside us.
Food also has value only when it enters our body.
Food has no value if its gets moldy on the counter. You have to eat it in order to be nourished. How frustrating for Jesus that the words are hardly out of his mouth when the literalists around him argue as if the metaphor were meant literally. He makes an odd choice here to continue to push ahead with the metaphor rather than try to explain himself. This, of course, only creates more misunderstanding.