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. After they arrive home, each player gets a DVD with host Allison Sweeney revealing their "at home challenge" - to run a half marathon - 13.1 miles! A cookie temptation adds an interesting twist to the competition, and the players find out the results of their hard work once they return to the ranch. Later, another contestant is sent packing.

The teams split up and the competition goes to playing as singles, and the weigh-in finds one player breaking a Biggest Loser record. (TV-PG)

PAST SEASON WINNERS ALI VINCENT AND MICHELLE AGUILAR GUEST STAR -- The contestants get a blast from the past this week with visits 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 contestants are also surprised by the arrival of some old friends, whose return promises to shake up the competition. And while one player is sidelined by medical issues, the rest compete in a balance and endurance challenge that finds each contestant standing on a platform, suspended six feet over a pool. One by one, the lines supporting the platform are removed, making it harder to stand, until only the winner is left standing. Later, Bob has last chance workouts at the beach before the weigh in, which is followed by a surprising elimination.