It's all about families in the new edition of The Biggest Loser, which features four husband-and-wife teams and four parent-adult child teams trying to lose weight through diet and exercise as they compete for a grand prize of $250,000. Trainers Bob Harper and Jillian Michaels fly around the country, surprising their teams with the news they've been chosen for the show. Then it's off to The Biggest Loser ranch in California, where the contestants get a wake-up call from the show's doctor about what ages their bodies really are vs. their chronological ages because of obesity. Then the eight teams compete in their first challenge -- and the lucky winner gets immunity from this week's elimination. Alison Sweeney hosts the hit weight loss series.