It was a common Catholic practice for generations, but it may be on its way back.

American Papist Tom Peters takes note of one small step in that direction from the bishop of Steubenville, who is “inviting” his flock to give up meat on Fridays for the unborn. N.B.: This move is not binding by law, and disregarding it does not constitute a sin (as it did in the pre-Vatican II days).

But it’s worth a look at what Bishop Conlon has to say about it:

I am asking that this be not only a penitential practice but also an experience of prayer and service. This can happen by connecting abstinence with our witness to the sacredness of human life. (In another section he says: Abstinence can also be service if we eat simple meatless food and donate the financial savings to the poor or to pro-life efforts.)

… The resumption of year-round abstinence in the Diocese of Steubenville will begin after this coming Easter, one week after Good Friday (April 17). Although the practice will not be a requirement of law, and failing to keep it will not constitute a sin, I hope every one who is old enough to receive Holy Communion and well enough to come to church will take it seriously. Our parishes, schools and organizations should provide meatless food at their Friday activities.

… the present challenge to the people in our diocese is not really radical. It is a call to what many if not most of us have put aside. And it is a way for us, like the apostles, to give up a little food and help Jesus feed the world.”

You can read more about abstaining from meat (or performing other forms of penance) on Fridays in this 1966 pastoral letter from the USCCB.