Christ often spoke mystically. Spiritual experience (always referencing the bible, as the “high minded” did, to look for whether, and if so how, it fits) is necessary to figure it out. This could even be a dual-meaning dictum like many in Scripture are. God is not averse to punning... what would you expect out of a joyful God?
I lean on the explanation by context. Passover seder, and the same words “this is” would be used over all the symbolic foods. The Passover Haggaddah as Jews have it goes back almost to gospel days and supports this strongly. Making it stand out as special here is something that happens when we lose sight of context.
You know, all this stuff about metaphors brings to mind examples of something like if you have a car accident and draw out the scene on a piece of paper and tell the insurance agent *This is my car.* and *This is his car.*
Well, I think that it’s clearly understood that the symbolism isn’t the real thing even though we say * This is...*
Passover was not only looking back at the first Passover in Egypt, but it was also looking forward to the Messiah coming. Just like communion is not only looking back as Christ’s death, but looking forward to His (soon, I hope) return again.
So the elements of the Passover meal represented things. The broken bread represented the broken body of Christ. Hence, *This is my body.*
It’s a word picture.