"The Church demands a certain amount of fasting before Communion. This is to remind us that the Eucharist is not only a sacrament of life, but also the sacrament of mortification. Only when we are stamped with the sign of the Cross will we be stamped with the glory of His Resurrection." Source: Ven. [...]
"Our Primitive Rule tells us to pray without ceasing. Provided we do this with all possible care (and it is the most important thing of all) we shall not fail to observe the fasts, disciplines and periods of silence which the Order commands; for, as you know, if prayer is to be genuine it must [...]
"The greatest devotion is called for at the moment of receiving this sacrament, because it is then that the effect of the sacrament is bestowed, and such devotion is hindered more by what goes before it than by what comes after it. And therefore it was ordained that men should fast before receiving the sacrament [...]
"To prepare for worthy reception of this sacrament, the faithful should observe the fast required in their Church. Bodily demeanor (gestures, clothing) ought to convey the respect, solemnity, and joy of this moment when Christ becomes our guest." Source: Catechism of the Catholic Church #1387
"Jesus has always many who love His heavenly kingdom, but few who bear His cross. He has many who desire consolation, but few who care for trial. He finds many to share His table, but few to take part in His fasting. All desire to be happy with Him; few wish to suffer anything for [...]
"Fasting ends lust, roots our bad thoughts, frees one from evil dreams. Fasting makes for purity of prayer, an enlightened soul, a watchful mind, a deliverance from blindness. Fasting is the door of compunction, humble sighing, joyful contrition, and end to chatter, an occasion for silence, a custodian of obedience, a lightening of sleep, health [...]
"Begrudge the stomach and your heart will be humbled; please the stomach and your mind will turn proud." Source: St. John Climacus, The Ladder of Divine Ascent