In the season opener, trainers Bob Harper and Jillian Michaels train 11 brand new couples, who begin the show with a combined weight of more than 3.5 tons.
It's off to an outdoor challenge, where the contestants race by sea kayak and then on foot to the top of a mountain, hoping to win immunity as well as a phone call home.
Alison Sweeney allows one player to reunite with their teammate at home and bring their trainer with them. But when fireworks erupt between the two teammates, one player accuses the other of not doing all she can to stay on the ranch.
First, a contestant is forced to leave the ranch for an important arrival back home. Later, things get tough when two teams that really need to remain at the ranch, fall below the yellow line. Also, pro football player Kurt Warner puts the contestants through one of their drills and Chef Curtis tests their knowledge of Super Bowl snacks.
The contestants' partners come back to the ranch. The team members who've been working out at home, weigh in to see how they have compared to their counterparts while away from the ranch. Finally, all the players compete in a "rope challenge," which leads to some tensions during eliminations when one player thinks her partner has been taking advantage.
The winner of a balancing competition, receives a 24-hour visit from someone back home. Next, the teams test their endurance, and later, one player is sent home from the team that falls below the yellow line.
The contestants find over 100 keys, but only two teams find the keys that unlock the gym. The remaining contestants have to learn to work out without the use of the gym.
Each team tries to bike as many miles as they can in a 24-hour period.
The contestants continue to adjust to their newly formed blue and black teams. They also meet Prevention Magazine editor Liz Vaccariello and take a pop quiz about health and aging. Then it's a grueling last chance workout leading up to weigh-in, after which Dane is eliminated.
Celebrity chef Rocco DiSpirito returns to the Biggest Loser to take the contestants to a restaurant, where he teaches them how to make healthier choices when eating out.
A pop challenge adds interesting twist to the weigh-in and later, the contestants will head to 24 hour Fitness for a relay race competition. The Black team wins and gets 24 hours of luxury, including spa treatments but some contestants have trouble resisting temptation during their 24-hour getaway.
All of the contestants head home for a week, where they are faced with the challenge of continuing to make healthy food choices and getting their workouts done in their home environments.
In part one of the two-part challenge, contestants divide the amount of weight they've lost so far among their opponents, with many ganging up on the player they feel is the strongest competitor.
The contestants get a blast from season five winner Ali Vincent and season six winner Michelle Aguilar, both filling in as host while Alison Sweeney is on maternity leave.
The competition heats up when the eight remaining contestants are faced with a temptation that will give the winner all the power. The players come to the gym and find 100 trays before them, under which there are high calorie snacks, cash prizes and the golden ticket.
Fashion guru Tim Gunn helps the final seven contestants look their stylish best after all the players get complete salon makeovers from guest hair stylist Tabatha and celebrity stylist Brandon Martinez.
The contestants' food and fitness knowledge is put to the test when Good Housekeeping Magazine's editor in chief stops by for a trivia challenge that will give the lucky winner an all-expense paid trip to New York.
The tables are turned when contestants get to train their trainers and are only too happy to put Bob and Jillian through the paces! Later, the remaining five players have to race up and down hills while carrying bags representing their total weight loss so far in a particularly grueling challenge.
The final four contestants go home for 30 days, reunite with friends and family, and experience the challenge of continuing to make diet and exercise a priority back at home.
All of the contestants from this season return for a special reunion and a chance to weigh-in one last time in front of a live studio audience. Eliminated contestants compete for the $100,000 prize, which Jerry wins. Finalists Tara, Helen, and Mike compete for the main prize of $250,000, which Helen wins after having lost a total of 140 lbs.