EVERAL YEARS AGO, an internet rumor was begun regarding an alleged indult given by Pope Pius XII to Catholics living in the United States. This indult allowed eating meat on the Friday following Thanksgiving.
Whether this rumor is accurate makes no difference, because the rules for Friday abstinence were changed in the 1960s.
Out of curiosity, several of my friends have been searching for documentation to prove conclusively whether this indult was ever given by Pius XII. I’ve never seen any proof, but that doesn’t mean the rumor is false. However, it’s important to remember that for Catholics alive today—even those of us who attend the Traditional Mass—this indult is completely irrelevant since the fasting rules were changed in the 1960s.
Just like any other Friday, Catholics are allowed to eat meat today if they substitute some other penance.
Church disciplines can change. The Eucharistic fast has changed through the years. The laws for fasting in Lent have also changed. A priest once said that Friday abstinence is the Church’s most neglected rule, and it would be difficult to argue with him: so few Catholics know about it these days! Someone told me that in England an effort was made to bring back the old Friday Penance; but I’m not sure if they ever did this and what level of compliance they got.
Meatless Fridays are a lovely and powerful gesture of love for our Lord. (By the way, 25 December is a Friday this year, so the Friday penance does not apply, since Christmas is a solemn feast.)
UPDATE (27 November 2020):
http://www.newliturgicalmovement.org/2020/11/on-mythical-pius-xii-thanksgiving.html