Jay Z Making Huge Life Change for 44th Birthday Photo Credit: Kevin Mazur/WireImage/Getty Images Rapper Jay Z turns 44 today, but don't expect him to celebrate with cake and ice cream. The "Holy Grail" musician, whose real name is Shawn Carter, has gone vegan, he revealed. Adorable Photo: Jay Z and Blue Ivy Share a Daddy-Daughter Moment On his blog, Life and Times, Carter wrote that for 22 days, he and his wife, singer Beyoncé, will be sticking to an entirely plant-based diet. "This all began a few months back when a good friend and vegan challenged me to embrace a "plant-based breakfast" every day," he wrote. It was surprisingly easier on me than I thought... What Did Blue Ivy Say When She Heard Jay Z's New Album The timing is especially significant for the couple, for whom four has always been a lucky number. (Not only is Carter's birthday Dec. 4, but Beyoncé"s is Sept. 4 and the couple was wed on April 4, 2008.) Plus, Carter explained, it takes 21 days to "make or break a habit," and, he added, "On the 22nd day, you've found the way." "There's something spiritual to me about it being my 44th birthday and the serendipity behind the number of days in this challenge; 22 (2+2=4) coupled with the fact that the challenge ends on Christmas day," he explained. It just feels right! Photos: What Other Celebs Are Vegans? Carter concluded by saying he'll continue to keep fans updated about his "spiritual and physical cleanse," and asked for vegan restaurant recommendations too. I don't know what happens after Christmas. A semi-vegan, a full plant-based diet? Or just a spiritual and physical challenge?" he wrote. We'll see...