In the US, we're permitted to substitute something else in place of meat. Unfortunately, we Catholics are terrible about actually doing it, partly because most Catholics are unaware that they're even supposed to be giving anything up. The bishops in the UK are actually restoring No-Meat Fridays starting next month, and I hope that the US bishops follow suit -- or at least get serious about enforcing the rule which exists now. That seems quite possible: Archbishop Dolan of New York wonders aloud if they're on to something, by restoring some externally-visible sign that we're Catholics. Making Catholics distinctively, visibly Catholics (through ashes, meatless Fridays, and the like) helps create a Catholic identity, and builds some roots for when times get tough.Can. 1249 The divine law binds all the Christian faithful to do penance each in his or her own way. In order for all to be united among themselves by some common observance of penance, however, penitential days are prescribed on which the Christian faithful devote themselves in a special way to prayer, perform works of piety and charity, and deny themselves by fulfilling their own obligations more faithfully and especially by observing fast and abstinence, according to the norm of the following canons.
Can. 1250 The penitential days and times in the universal Church are every Friday of the whole year and the season of Lent.
Can. 1251 Abstinence from meat, or from some other food as determined by the Episcopal Conference, is to be observed on all Fridays, unless a solemnity should fall on a Friday. Abstinence and fasting are to be observed on Ash Wednesday and Good Friday.
Can. 1252 The law of abstinence binds those who have completed their fourteenth year. The law of fasting binds those who have attained their majority, until the beginning of their sixtieth year. Pastors of souls and parents are to ensure that even those who by reason of their age are not bound by the law of fasting and abstinence, are taught the true meaning of penance.
Can. 1253 The conference of bishops can determine more precisely the observance of fast and abstinence as well as substitute other forms of penance, especially works of charity and exercises of piety, in whole or in part, for abstinence and fast.
But there are a few other reasons for the practice, in addition. I just read a great reason in Graham Greene's The Power and the Glory, in which the priest explains the practice like this: "Discipline is necessary. Drills may be no good in battle, but they form the character." That's a good way of thinking about it. St. Paul, in Ephesians 6:12, says:
If we take St. Paul seriously, then one of the jobs of the Church is to prepare each of us for spiritual warfare against the forces of Hell, as well as to fend off the spiritual temptations of this world. The Church can't just send us off to fight with good intentions. Spiritual discipline is absolutely necessary. I don't need to tell you what happens when She totally relaxes that discipline - we've already seen, and it's been a disaster.For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms.
But there's a reason that it's important we specifically do No-Meat Fridays, and there's a reason that the Early Church Fathers, like Tertullian and Clement, testify to this practice from the beginning.
What's given up isn't technically "meat" but the Latin "caro," which means "flesh." This is why fish is allowed: their meat isn't considered "flesh." So why do we give up flesh on Fridays? Two reasons.
First, "flesh" is often the term the New Testament writers (particularly St. Paul) use to describe our sinful appetites. So in Romans 8:13, Paul says, "For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live." We give up "flesh meat" to symbolize putting to death the deeds of the flesh.
Second, Christ Redeemed us by offering up His Flesh for our salvation on Good Friday. St. Paul explains in Colossians 1:19-23:
So Christ, by being put to Death in the Flesh, reconciles us to the Father. So our job is done, right? Christ bore all the bad stuff, so we're home free? Not quite. St. Paul says in the very next breath (Colossians 1:24-25):For it pleased the Father that in Him should all fullness dwell, and having made peace through the blood of His Cross, by Him to reconcile all things unto Himself -- by Him, I say, whether they be things on earth or things in heaven.
And you, who were once alienated and enemies in your mind by wicked works, even now hath He reconciled in the body of His flesh through death, to present you holy and unblamable and unreprovable in His sight, if ye continue grounded and settled in the faith, and be not moved away from the hope of the Gospel, which ye have heard and which was preached to every creature under heaven, of which I, Paul, am made a minister.
I now rejoice in my sufferings for you, and fill up that which is lacking of the afflictions of Christ in my flesh, for His body's sake, which is the church, of which I am made a minister according to the dispensation of God, which is given to me for you, to fulfill the Word of God-- even the mystery which hath been hid from ages and from generations, but now is made manifest to His saints.Just read that passage a couple times, and tell me that St. Paul wasn't a Catholic. Christ being put to Death in the Flesh reconciles us to God the Father, but the Passion doesn't mean that we're going to free-ride. Rather, our job is to take up our cross daily, and follow Christ (Luke 9:23). A Cross is a for killing: Christ is saying that we have to die to ourselves every day. So it's fitting that we put away the flesh-meat on Friday, the day of week which forever honors Christ's Passion, to signify both our love of the ultimate Sacrifice of the Flesh, and to emulate our Savior by mortifying the flesh for the sake of the Spirit.