I recently came across the above meme on a Catholic Website; it reflects, albeit in a comical manner, the common Roman Catholic claim that the phrase, "this is my body," as well as "this is my blood" is to be taken "at face value" (i.e., everything but the outward appearance of the bread and wine are substantially changed into the body, blood, soul, and divinity of Jesus). How does this argument hold up to exegesis?
The phrase, "this is my body" translates the Greek phrase τουτο εστιν το σωμα μου literally, "this is the body of me." A rather technical argument has been made to support transubstantiation by some Catholic writers. The argument is that as the demonstrative "this" τουτο is a demonstrative neuter singular, it cannot refer to the term "bread" αρτος which is masculine, but the noun "body" σωμα which is neuter. As a result of this, and the fact that it is coupled with the verb ειμι "to be," Christ is teaching that the bread becomes the body of Jesus, with an alternative translation being, "this [new entity] is the body of me."
It is correct that the referent for the demonstrative "this" is "body." However, to read "is" in a literalistic way as to argue that Transubstantiation is in view in the narratives is vacuous.
In Greek grammar, there is what is called an "interpretive ειμι," wherein the verb ειμι, often in conjunction with τουτο or τι, has the definition of "meaning" or "[this] means."
Two notable instances of such can be seen in Matthew 27:46 and Luke 18: 36--
And about the ninth hour Jesus cried with a loud voice, saying, Eli Eli, lama sabachthani, that is [τοῦτ᾽ ἔστιν] to say, My God, my God, why has thou forsaken me? (Matthew 27:46)
And hearing the multitude pass by, he asked what it meant [εἴη τοῦτο]. (Luke 18:36)
A symbolic meaning of "this is my body" can still be retained, notwithstanding claims to the contrary. Furthermore, taking "is" in such a literalistic manner that many who hold to the dogma of Transubstantiation, or something similar, such as the Eastern Orthodox view do, results in some inanities if one were to be consistent in their approach to the verb ειμι. For instance, in Luke 22:20, both "cup" (ποτηριον) and the demonstrative are singular neuters. However, in Catholic theology, it is not the cup, but the contents thereof (i.e., the wine) that become transubstantiated into the blood of Christ. Of course, just as "this is my body" is a literary device (the interpretative ειμι) and should not be taken in a literalistic fashion, neither should "this cup" be interpreted as being the [blood of] the new covenant; in reality, it too, is a literary device (synecdoche).
Another related argument is that the use of τρωγω in John 6:54f is "proof" of Transubstantiation; for a refutation, see my post here.
Of course, a close identification of the bread and wine with the body and blood of Christ is not problematic for LDS theology and Scripture; consider the following from the Book of Mormon (which records the very words of Christ Himself):
And this shall ye always observe to do, even as I have done, even as I have broken bread and blessed it and given it unto you. And this shall ye do in remembrance of my body, which I have shown unto you. And it shall be a testimony unto the Father that ye do always remember me. And if ye do always remember me ye shall have my Spirit to be with you . . . And now behold, this is the commandment which I give unto you that ye shall not suffer any one knowingly to partake of my flesh and blood unworthily when ye shall minister it; for whoso eateth and drinketh my flesh and blood unworthily eateth and drinketh damnation to his soul; therefore it ye know that a man is unworthy to eat and drink of my flesh and blood ye shall forbid him. Nevertheless, ye shall not cast him out from among you, but ye shall minister unto him and shall pray for him unto the Father, in my name; and if it so be that he repenteth and is baptized in my name then shall ye receive him, and shall minister unto him of my flesh and blood. (3 Nephi 18:6-7, 28-30)