greenwald is a vegan and has appeared in at least two ads for peta. he told peta his reasons for going vegan: "in college i stopped eating red meat on a bet with my girlfriend at the time. she bet she could stop smoking, and i bet that i could stop eating red meat. she started smoking again, so i won, which i'm always proud of.…i had been a vegetarian as a child for whatever reason. i guess kids sometimes follow their instincts…my friend dared me to go vegan as i was reading this book "fast food nation", which opened my eyes to a lot of cruelties.…ever since then, i've been vegan and enjoyed it daily."