The Biggest Loser

The Biggest Loser is a reality television series. The original American version started airing on October 19, 2004. Many other countries have their own versions. 
It was originally hosted by Caroline Rhea from 2004 to 2006. In 2007 starting with the fourth season, Alison Sweeney took over as host. In 2015, Sweeney left as host and trainer Bob Harper took over as host for the 17th season that aired in 2016.
Bob Harper and Jillian Michaels were the original personal trainers of the show when the show got on the air. Since then trainers such as Cara Castruonova, Jessie Pavelka, Kim Lyons, Brett Hoebel and Anna Kournikova have also trained on the show. The current trainers are Dolvett Quince and Jennifer Widerstrom.
A spin-off called "Losing It with Jillian" aired in the summer of 2010.
It originally aired in standard definition, but started airing in high definition in the 10th season.
No new seasons have aired since 2016. While the show has not been formally cancelled, the show is being investigated as to whether contestants were given drugs.
"The Biggest Loser" also airs internationally in many other countries.