That's why the Orthodox Church doesn't try to "explain" the Mysteries of God. We know the universe exists, but we don't know why. Rationalization doesn't lead to faith, it leads to rationalism, a belief in one's own "explanation."
Jesus' body and blood really is present in the bread and wine. He is truly there, but the bread and wine still appear to be bread and wine
But that is exactly the difference, redgolum. Jesus' Body and Blood are not "in" the bread and wine. We say that "this is truly Thine Body...and Blood." The Lutheran wording makes it sound like it's some kind of a "sandwich" and "tea with honey."
The "nature" of sacramental changes are subtle to our senses. They are "real" in that (in the Aristotelian sense) the bread and wine "cease" to be bread and wine and become something they were not before.
The only difference is that spiritual changes are not physically discernible, whereas physical changes in Aristotelian philosophy are. Thus, a match is no longer "a match" when it is burned; it ceases to be a match.
We know that because the match no longer "looks" like a match, but instead looks like a "burned match," which is incapable of striking fire as a match can.
Obviously, when one is baptized, there is no physical change. One cannot tell a baptized baby from a non-baptized one just by looking at them, but the baptized baby is no longer the same being it was before baptism.
In the West, it is a must to "explain" everything, otherwise we cannot believe anything because we can believe only that "which makes sense" (now that's an oxymoron if I ever heard one!).
The West is rooted in the deification of reason and to some extent humanization of God: man is the final arbiter of what's possible and what's impossible, even God. Thus, there is a "need" to rationally "prove" the irrational.
All things considered, the Orthodox declaration on the Eucharistic Mystery is simply based on faith and not on reason. We supplicate God to send the Holy Spirit and change the Bread and the Wine, to make them the Body and Blood. The mechanism of God's mysteries are left to God.