The
Eastern Orthodox Church, like the Catholic Church, teaches that the bread and wine truly become the body and blood of Christ. (Although the four-syllable word "metabole"/"metavole" may be loosely said to be "Greek Orthodox for 'transubstantiation'", it actually means "change" or "alteration". Greek for "transubstantiation" as in "an alteration specifically of the fundamental substance or essence" in the Roman Catholic sense would be "metousiosis".) Orthodox theologians have tended to refrain from philosophical reflections such as those of the Medieval Scholastics. Rather, they prefer to refer to the Eucharist as a "mystery", with the full understanding beyond human comprehension, which is also an expression used freely among Catholics.
[1] Most Orthodox theologians would prefer to say too little about the details and remain firmly within Holy Tradition, than say too much and possibly deviate from the truth.