But contestants told the New York Post that the National Institute of Health study didn't take into consideration the "corrupt" tactics carried out by The Biggest Loser producers behind the scenes. Contestant Kai Hibbard from season three said her hair started falling out from The Biggest Loser's strict regime. Credit:NBC Resident doctor for the series Rob Huizenga - also known as Dr H - reportedly encouraged contestants to take Adderall, a stimulant often prescribed to those with ADHD, and pills containing Ephedra, a weight-loss aid banned by the Food and Drug Administration in 2004. Joelle Gwynn, who was trained by Bob Harper in 2008's "couples" season claimed Harper's assistant gave her a bag of undescribed pills during the series. "He says, 'Take this drug, it'll really help you.' I was like, 'What the f- -- is this?'"

"I felt jittery and hyper. I went and told the sports medicine guy. The next day, Dr H gave us some lame explanation of why they got added to our regimen and that it was up to us to take them." The Biggest Loser's Harvard-trained doctor Rob Huizenga speaks to a contestant. Credit:NBC Suzanne Mendonca from season two said contestants were "passing out" in Huizenga's office before the final weigh-in from taking amphetamines and diuretics. "On my season, five people had to be rushed to the hospital. He knew exactly what we were doing and never tried to stop it." An American Biggest Loser contestant celebrates her weigh-in. Credit:NBC via Getty Images

"They would take their spin bikes into the steam room to work up a sweat. I vomited every single day. Bob Harper tells people to throw up: 'Good,' he says. 'You'll lose more calories'." Both NBC producers and Huizenga denied the claims, saying contestant's health was their biggest priority. "We prohibit the use of any illegal substances, in addition to the many other rules and procedures of the show that are designed to ensure safety," the network said in a statement. Season two contestant Mark Yesitis said he lost seven kilograms of water weight before the finale, claiming he "was probably near death". "I had my gall bladder removed. I'd never had issues with my gall bladder before the rapid weight loss."

"The day after my surgery, I ran five miles (eight kilometres). My doctor was very angry. But that's how brainwashed I was." Australian Biggest Loser Trainer Michelle Bridges was criticised last month for "fat-shaming" after she told ABC's Australian Story: "I am yet to have met someone who is morbidly obese and happy". Former host Ajay Rochester accused Bridges of being "fat-phobic" in a blog post and said she was "miserable and painfully thin" while hosting the show. Rochester said she was: "starving to keep my job and make my TV bosses happy and working out at 4am before working an 18 hour day only to go home and have water for dinner." The Biggest Loser premiered in the United States in 2004 and has been developed in more than 30 countries. An Australian version ran on Channel Ten from 2006 to 2015.