The historical practice that this occurred in the context of... the Passover seder meal... is metaphor oriented. So this isn’t a big problem to me.
I’d also want to ask those who propound such a view: what do you mean by body, if wine and bread can be it. Any kind of actual definition for body leaves us high and dry here.
Jesus also said He was drinking the “fruit of the vine” not blood.
Matthew 26:29 But I say unto you, I will not drink henceforth of this fruit of the vine, until that day when I drink it new with you in my Father's kingdom.
The last or 4th wine in a Seder service was the Gaul accepted by Christ on the cross. The 1st 3 were taken in the upper Room.
Christ said you must Eat my Body and drink my Blood if you want Eternal Life. In gospel of John some Jews began to openly complain that it was repulsive to think about eating his Body & Blood. Christ called them Out and said you must or you reject me! The Majority got up and left! The Apostles were asked the same thing. They Said Jesus you are the WAY and the light the True God & man where would we go?
The Bread came in two examples 1st Book of Genesis Melchizedek also known as King of Salem just won a battle and celebrated the victory by Offering Bread & wine in Thanksgiving to GOD for the Victory.
2nd Example was the Mana from Heaven in exodus with Moses. This bread you ate but weren’t fulfilled. Christ was the True mana from heaven that gave us eternal LIFE.
The Entire new testament is the new Covenant the Only Covenant of the new testament. The Body blood soul and divinity of our LORD Jesus Christ who died for our sins and those of the WHOLE world.
Every Book in the New testament contributed to the Liturgy of the Eucharist which in 110 AD became the HOLY Mass with the Holy Eucharist as the center of the Mass. You Can read Early Church fathers in 1st century they talk of the REAL Presence in the Eucharist.
The Didace was the Apostles teaching tool in their Boot Cams for Evangelization. It was like the 1st Catechism ENJOY
http://www.hprweb.com/2014/05/appreciating-the-ancient-roots-of-church-precepts-the-didache-revisited/