4x1 - Back to Basics

September 11, 2007

The contestants start off their weight-loss journey by being dropped off in the middle of the desert, while their trainers standby about a mile away from them. The first two to reach their trainers will become the team captains, allowing them to pick their five teammates. However, this means the six remaining contestants have to be sent home, but Jillian Michaels returns to let them in on a little secret.

4x2 - The Secret Black Team is Revealed!

September 18, 2007

Bob and Kim prepare their teams for this week's challenge: racing up the stairs of a 10-story building. With immunity as the prize, both teams will have to do their best. Meanwhile, the secret black team, trained by Jillian Michaels, is finally revealed to the other contestants, who will join them in competing for the title of "The Biggest Loser" and ,000.

4x3 - The Pressure of Temptation

September 25, 2007

When the teams are put in a room full of tempting, unhealthy foods, they will have to decide in four minutes if it is worth it or not to eat the most calories in order to win a three-pound pass which can be used to their advantage at the weigh-in. In the challenge, the contestants will compete in three different 100-meter heats against a yellow team formed by three kids, where the winning team will win a phone call home.

4x4 - Bidding Wars

October 2, 2007

Another food temptation this week puts the trainers to the test instead of the contestants. Should Bob, Kim or Jillian give in to the temptation, it will give their team a 15-second advantage in the physical challenge. The challenge consists of the contestants running up and down a hill to reach their team flag in the fastest time. However, there is one catch: the teams will have to outbid each other with a faster time in hopes that someone will wager lower and lose, which will end up knocking out a team.

4x5 - Surprise Getaway

October 9, 2007

Alison surprises all three teams with an exotic getaway vacation, but they soon learn that they will be faced with temptations and challenges unlike any they have faced at the campus. Later, after the weigh-in, those who lost will try to forge an alliance with the others before deciding who to vote off.

4x6 - Lively Beach Competition

October 16, 2007

4x7 - Weigh-In Shocker

October 23, 2007

4x9 - Biggest Losers Go Green

November 6, 2007

4x10 - A Taste of Home

November 13, 2007

4x11 - Memorable Makeovers

November 20, 2007

4x12 - Viewers Choose the Challenge

November 27, 2007

4x13 - A Slice of Temptation

December 4, 2007

4x14 - Five Remaining Players Compete for Spot on Finale

December 11, 2007

4x15 - "Biggest Loser" Revealed in Season Finale!

December 18, 2007