The Biggest Loser features obese people competing to win a cash prize by losing the highest percentage of weight relative to their initial weight.

The Biggest Loser is an Australian reality television show, based on the original American version of the same name. It is produced by Crackerjack Productions and screened on Network Ten. It was hosted by Ajay Rochester from 2006–2009 and introduced former Olympian Hayley Lewis as its host in 2010. The show first debuted on 13 February 2006, followed by a second season on 4 February 2007 which introduced Michelle Bridges, Shannan Ponton and Steve Willis. The third season began airing on 3 February 2008. A fourth season, which features couples competing as teams, started airing on 1 February 2009. A fifth season, which aired on 31 January 2010, featuring former Olympic swimmer Hayley Lewis as the new host, and in 2011 the show introduced the new trainer Tiffiny Hall.

Contestants transform mentally and physically as they compete to lose weight and win a cash prize.