You've got one sharp memory! Absolutely correct but bad timing for McD. Shortly after they introduced the Filet-o-fish, the church announced that one could eat meat on Fridays ... IF ... they sacrificed something else. Unfortunately, most catholics only heard the first part of that announcement, and celebrated by slapping a steak on the grill :-)
Here is the appropriate section of canon law:
From the 1983 Code of Canon Law:Can. 1249 All Christ's faithful are obliged by divine law, each in his or her own way, to do penance. However, so that all may be joined together in a certain common practice of penance, days of penance are prescribed. On these days the faithful are in a special manner to devote themselves to prayer, to engage in works of piety and charity, and to deny themselves, by fulfilling their obligations more faithfully and especially by observing the fast and abstinence which the following canons prescribe.
Can. 1250 The days and times of penance for the universal Church are each 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 Episcopal Conference can determine more particular ways in which fasting and abstinence are to be observed. In place of abstinence or fasting it can substitute, in whole or in part, other forms of penance, especially works of charity and exercises of piety.
The USCCB established the fasting norms for those of us in the US in their "Pastoral Statement on Penance and Abstinence"
22. Friday itself remains a special day of penitential observance throughout the year, a time when those who seek perfection will be mindful of their personal sins and the sins of mankind which they are called upon to help expiate in union with Christ Crucified.23. Friday should be in each week something of what Lent is in the entire year. For this reason we urge all to prepare for that weekly Easter that comes with each Sunday by freely making of every Friday a day of self-denial and mortification in prayerful remembrance of the passion of Jesus Christ.
24. Among the works of voluntary self-denial and personal penance which we especially commend to our people for the future observance of Friday, even though we hereby terminate the traditional law of abstinence binding under pain of sin, as the sole prescribed means of observing Friday, we give first place to abstinence from flesh meat.
We do so in the hope that the Catholic community will ordinarily continue to abstain from meat by free choice as formerly we did in obedience to Church law. Our expectation is based on the following considerations:
a. We shall thus freely and out of love for Christ Crucified show our solidarity with the generations of believers to whom this practice frequently became, especially in times of persecution and of great poverty, no mean evidence of fidelity to Christ and His Church.
b. We shall thus also remind ourselves that as Christians, although immersed in the world and sharing its life, we must preserve a saving and necessary difference from the spirit of the world. Our deliberate, personal abstinence from meat, more especially because no longer required by law, will be an outward sign of inward spiritual values that we cherish.