1. Former Beatle, Paul McCartney, and Yoko Ono, the artist of wife of another Beatle, John Lennon, have both come out in favour of a Meatless Day:
www.grist.org/. . . mccartney-yoko-meat-free-mon/

2. FARM (Farm Animal Rights Movement) has long campaigned for Meatless Mondays: www.meatoutmondays.org/index.php

3. Many Buddhists refrain from meat twice a month, on the 1st and 15th of the lunar calendar. Now, the idea has been raised to extend the practice to once a week. This idea might be useful with other religions that have meatless days.