Is Thomas More's reading of "This is my body" a literal one by modern standards? Thomas More, whose birthday it is today (7 February),
was a strong defender of Catholic eucharistic theology.
In his Answer to a poisoned book (1533),
a reply to a Zwinglian
tract probably written
by George Joye,
he wrote:


  I shall, beside all such spiritual expositions
  as this man useth therein by way of allegories or parables,
  declare you the very literal sense of those words,
  "My flesh is verily meat, and my blood verily drink":
  so that that ye may see thereby
  that our saviour verily spake and meant,
  not only such a spiritual eating as Master Masker
  saith he only meant,
  but also the very bodily eating and drinking
  of his very flesh and blood indeed. 1


The basic dispute
depends upon what the meaning of the word "is" is,
in the words of institution, and
in other passages 
like the one quoted (John 6:55).
Zwingli and Joye thought it meant "signifies".
More asserts (among other arguments) that since Jesus had a body of flesh and blood,
"This is my body" admits a literal reading,
unlike when Jesus elsewhere says that he "is" a vine, a door, and so on.
He says that although there are also symbolic meanings, 
a literal one cannot be wholly dismissed, since that would mean ignoring the plain words. 
Moreover, although one has to go to some effort to explain how it's possible (how Christ's body can be present in the Eucharist, at many places and times, appear as bread, etc.), it's more acceptable to believe in miracles than to remove all literal meaning from "is".

At first glance this seems to be the same kind of argument
made by Biblical literalists today about many other passages. Does More's reasoning - that it is necessary to find some plain reading if at all possible - count as a "literal" argument, according to a modern understanding about what that means? What rules or safeguards are present in the modern approach, whereby self-described literalists today are generally not led to consider transubstantiation a viable option in this case, when supernatural explanations are accepted in other cases?

1. The answer to the first part of the poysoned booke
whych a nameles heretike hath named the supper of the Lord, 1.3. In The workes of Sir Thomas More ... in the Englysh tonge (London, 1557), p1042.
Spelling and punctuation modernised by me.
Hyper-Literalism

This seems to be a case of taking the Scriptures too literally when it is intended to be symbolic.

If Christians are the "light of the world", as Jesus said in John 8:12, then all we would need to do to see if someone is a Christian or not would be to turn out all the other lights and see if the person gives off any light himself.

All people who ever hated anyone would be convicted of murder (Matthew 5).  Jesus is a door to a sheep pen where he keeps his sheep and shepherds them, but He Himself was also a sheep who could talk, or at least half man, half sheep.  No, God became a Man--not a sheep.

The Bread and the Wine

The reason that most Protestants reject the notion that the elements of communion are literally the body and blood of Christ is that when Jesus said those words, He was referring to literal bread and literal wine, neither of which was His body or blood.

Also, Paul refers to Jesus as our Passover in 1 Corinthians:


  For Christ, our Passover lamb, has been sacrificed. 1 Corinthians 5:7


It was the Passover celebration that Jesus was celebrating with His disciples when He spoke of His body and blood.  The bread was unleavened bread.  Leaven was symbolic of sin, so the unleavened bread represented the sinlessness of Christ.  

So, there is ample evidence that this was always to be understood as symbolic.  

Taking things as literal when they were mean to be symbolic is definitely problematic and distorts the Scriptures as much as those who symbolize things that were clearly intended to be literal.