Bob Harper is a world-renowned fitness trainer and star of the NBC reality series The Biggest Loser, which finished thirteenth season in 2012. With several bestselling fitness DVDs, his own line of supplements, an online fitness club, as well as the inspirational book Are You Ready? to his credit, Harper still teaches a local spin class where he resides in Los Angeles with his dog Karl. Greg Critser is a longtime science and medical journalist. The author of the international bestseller Fat Land: How Americans Became the Fattest People in the World, he lives in Pasadena, California.