There are a number of theories about how we truly eat and drink the body and blood. The Reformed view is that Christ is not physically present here on earth, because he ascended to heaven, and there he will remain until he returns. Nevertheless, the power of his resurrected immortality is truly communicated to us by the Holy Spirit, so that we truly eat and drink, albeit in a spiritual manner, not a gross corporeal manner.
When they (the Reformed) speak of the presence of the body and blood of Christ in the Supper, they do not mean that they are present upon earth, except with respect to faith], that is, that our faith, reminded and excited by the visible signs, just as by the Word preached, elevates itself and ascends above all heavens, and receives and enjoys the body of Christ, which is there in heaven present, yea, Christ Himself, together with all His benefits, in a manner true and essential, but nevertheless spiritual only. For [they hold that] as the bread and wine are here upon earth and not in heaven, so the body of Christ is now in heaven and not upon earth, and consequently nothing else is received by the mouth in the Holy Supper than bread and wine. Formula of Concord.
Another explanation is that we are taken up to heaven, where Christ is, and in this way we truly eat and drink the body where it is present. I don’t know what to think about that, because no-one I know has ever been transported away during the Supper. I am a literal thinker, and if we are taken to heaven then it has to be in the body, or it is just another figure of speech that I cannot make head or tail of.
… our faith, reminded and excited by the visible signs, just as by the Word preached, elevates itself and ascends above all heavens, and receives and enjoys the body of Christ, which is there in heaven present, yea, Christ Himself, together with all His benefits, in a manner true and essential, but nevertheless spiritual only.
Luther – good man – taught that the corporeal body and blood are present in the Supper, and are consumed physically by means of the mouth. He had a very dim view of the Reformed doctrine, which he held to the end of his life.
… we confess that in the Lord’s Supper the body and blood of Christ are truly and substantially present, and are truly tendered with the visible elements, bread and wine, to those who receive the Sacrament. For since Paul says: “The bread which we break is the communion of the body of Christ,” etc., it would follow, if the body of Christ were not, but only the Holy Ghost were truly present, that the bread is not a communion of the body, but of the Spirit of Christ. Formula of Concord.
Luther’s argument boiled down to one point, that there are no indicators in the words of institution that they are to be taken figuratively, and that they must must therefore be taken literally.
The essence of the Reformed position is that Christ is human, and that a human body cannot be in more than one place at a time.