The majority of Protestantism has reduced the sacrament of the Lord's Supper as being just a symbolic ritual with no regards for any sort of "presence" in the bread. In other words, the bread and wine do not actually literally turn into the Body and Blood of Christ. This is where theology, philosophy and science mix in to the debate. Anti-catholics think that it is illogical and "against common sense" for bread to have turned into flesh when it is still physically bread. At the same time, they accept the fact that a virgin can actually give birth and that there was even a God (a Triune God too) in the first place! They also for some reason keep on saying that Catholics practice pagan idolatry during Mass by sacrificing Christ.
==> Eucharist (Catholic Encyclopedia)
==> Sacrifice of the Mass (Catholic Encyclopedia)
==> The Real Presence of Christ in the Eucharist (Catholic Encyclopedia)
==> The Blessed Eucharist as a Sacrament (catholic encyclopedia)
==> what Luther taught...
==>Here is a Lutheran view of 1 Cor 11 on the "Body" of Christ.