Austin Andrews

This week kicks off with host Alison Sweeney issuing a challenge to the ranch-based contestants: if they have a higher percentage of weight loss than the "unknowns" -- the contestants working out with the two new mystery trainers -- they'll all have immunity this week. The "unknowns" fuel the competitive spirit by delivering messages and surprises to the contestants at the ranch reminding them just how tough their competition really is. Then Dr. Huizenga gives sobering news to contestants about their health risks and their real ages vs. their chronological ages, but this time, loved ones from home are involved to really help drive the message home. Later, the ranch contestants' ability to work together as a team is tested when they try to beat the time of the unknowns in a wild bridge-building challenge using rafts. Then a tense weigh-in reveals whether the ranch contestants are safe from elimination, or whether they'll be sending another player home.

Two new trainers and a compelling new twist deliver a game-changing season like nothing viewers have seen before when season 11 premieres with twenty-two contestants -- eleven family and friend teams of two. After the first challenge, contestants are given the unprecedented opportunity to choose whether to work out with trainers Bob Harper and Jillian Michaels at the ranch - or work out at a secret location with two unknown trainers and get four weeks of immunity. What ensues is a riveting ride of intense emotions, surprising turns and "can't miss" moments as the two groups fight their weight loss battles separately with two sets of trainers equally committed to giving these players a new lease on a healthier life. The contestants include an Olympic gold medalist, identical twin policemen, a pastor who wants to spare his overweight son from the challenges he faced because of obesity, and a woman who has lost pregnancies because of her weight and wants more than anything to be a mother. Alison Sweeney hosts the series.

The "unknown trainers" are finally revealed, and both will share their personal stories that led them to "The Biggest Loser." Their contestants, "the unknowns," confront one player they feel isn't working hard enough, and later, "the unknowns" and the ranch contestants square off for a pop challenge. The winning player from each group will get a delicious healthy dinner prepared by Chef Curtis Stone, and compete for a coveted 2 lb. advantage at this week's weigh-in. Later, Dr. Huizenga gives "the unknowns" startling news about their health, and one player is surprised to learn they have the highest percentage of body fat in the group. Meanwhile, trainers Bob Harper and Jillian Michaels single out a few of their contestants to find out what really led to their weight gain, and then the ranch contestants meet host Alison Sweeney for a water-carrying challenge that will give the winner the sole vote at this week's elimination. Later, a surprising weigh-in -- which results in shocking numbers for one team -- disappoints the trainers in a big way, leading to the elimination of one player they feel isn't ready to go home.

A ball challenge that turns out to be much harder than it looks gives the winning team a big advantage at this week’s weigh-in, which is especially valuable given that both a red line and a yellow line will result in two players going home. Trainers Bob Harper and Jillian Michaels try to teach their contestants to push beyond the limits they’ve set for themselves, while trainers Cara Castronuova and Brett Hoebel take their team for an intense workout at a Mixed Martial Arts gym owned by contestant Rulon Gardner’s former trainer, retired UFC heavyweight champion Bas Rutten. Then a weigh-in filled with surprises is followed by two contestants leaving the ranch. Alison Sweeney hosts the series.

It's Valentine's Day on the ranch, and host Alison Sweeney ushers the contestants into a room full of chocolate candies for a holiday-themed temptation. Whoever eats the most chocolate will have the option to trade two players on their team for two players on the other - or to keep the teams the same, and the winner will be a secret. But as teams are divided into red vs. black, the winner's choice causes upset in the house. Later, a five-part relay race challenge tests the players' endurance, speed, agility, strength and knowledge. Trainer Jillian Michaels takes one contestant horseback riding, and one team gets to enjoy heartwarming videos from home before a weigh-in results in a Biggest Loser record being broken and another player heading home.