The Biggest Loser 'The Biggest Loser's longtime trainer Bob Harper will host Season 17 09/08/2015 The Biggest Loser's Bob Harper is switching roles again. Read More RELATED NEWS 'The Biggest Loser: Temptation Nation' premiere to feature "health or wealth" temptations and return of trainer Jessie Pavelka'The Biggest Loser' Season 17 cast, premiere and format revealed by NBC'The Biggest Loser's longtime trainer Bob Harper will host Season 17 TAGS: The Biggest Loser Bob Harper Alison Sweeney Ben Silverman
