Advertisement'Biggest Loser' Lessons: Why The Body Makes It Hard To Keep Pounds OffMay 02, 2016NPR StafffacebookEmailDanny Cahill (left) won Season 8 of The Biggest Loser in 2009 by losing an amazing 239 pounds. He's pictured with at-home prize winner Rebecca Meyer. In the years since, Cahill has put back on more than 100 pounds, he told The New York Times. (NBC via Getty Images)