So then.. you don't "like" metaphors and believe them to contain not MORE information bur LESS.. That metaphors are not a richer more detailed example of discourse but an example of unnecessary information?.. And Jesus who used metaphor almost exclusively.. was not very clear in his speaking.. You know; GOD, that has a public speaking problem..
One wonders what "other" of Jesus spiritual metaphors have you missed... and counted them literal..
And while I'm not especially interested in kumbaya as a life-style, it seems to me the Eucharist is so rich a thing that there must be acres of areas in which we can find agreement. There's a lot in Calvin to love, IMHO.
In this particular instance, John 6, the scripture records Jesus explaining that He is not speaking in metaphores; St. Paul likewise explain the Eucharist as real presence of Christ in 1 Cor 11:29. At other times the metaphorical character of His speech is clear from the context. If you have specific question about any passage, please ask me, and I will try to give you what the Church teaches as accurately as I can.