Last updated: May 23, 2016

More troubling news has surfaced about The Biggest Loser. 

Earlier this month, a study published in the journal Obesity revealed that 13 out of 14 former contestants, who each lost an average of 100 pounds on the NBC hit show, were unable to keep the weight off six years later. The study findings suggest that changing metabolic rates and shifting levels of the appetite-regulating hormone leptin made it difficult for participants to maintain their slimmer physiques.

Now a new article in the New York Post alleges that the show encouraged some seriously unhealthy dieting tactics, which may also be to blame for the contestants' ultimate weight gain.

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The Post quotes multiple sources who claim the show pushed them to take diet pills and severely restrict their caloric intake in order to shed pounds. One anonymous source said Biggest Loser trainer Bob Harper supplied contestants with Adderral and weight loss pills containing ephedra extracta substance the FDA banned in 2004 after it caused several deaths. 

Another source, Joelle Gwynn from the 2008 "Couples" season, said Harper instructed her to lie on-camera about how many calories she was consuming. Gwynn says Harper told her to say she was eating 1,500 calories a day, while he was actually pushing her to have just 800, "or as little as you can."

"People would take amphetamines, water pills, diuretics, and throw up in the bathroom," Season 2's Suzanne Mendonca told The Post. "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.’ "

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Many of the sources claim the show's resident doctor, Rob Huizenga, MD (often referred to as Dr. H.), knew and supported these unhealthy practices. "People were passing out in Dr. H’s office at the finale weigh-in," Mendonca said. "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."

Dr. Huizenga—who collaborated with researchers for the Obesity study—is strongly denying these claims. "Nothing could be further from the truth,” he wrote in an e-mail to The Post. "Contestants are told at the start of the show that there is zero tolerance for any weight-loss drugs. Urine drug screens and the evaluation of serial weights are repeatedly used to flush out possible illicit use."

The show's producers are also refuting the claims. In a statement to The Post they stressed that the use of illegal substances is prohibited on the Biggest Loser: "The safety and well-being of our contestants is, and always has been, paramount."