Shocking Revelations From 'Fit for TV: The Reality of The Biggest Loser' — Including Contestants Being Fed Caffeine Pills to Almost Dying and More

In the documentary, The Biggest Loser Season 2 alum Suzanne Mendonca recalled telling the producers she had begun exercising and eating healthy meals. Instead of supporting the path she was on, she reportedly received a negative response.

"They would say, 'No, we don't want you to do that. We want you to gain more weight,'" she continued. "I wanted to be on the show so badly that I did gain extra weight."

Mendonca pointed out the show eventually caused her to lose her sense of identity, stating, "I didn't know who I was, financially, emotionally, mentally, physically. I came back with a severe eating disorder. I stopped eating."

According to Yukich, she "cheated death" when she contracted a rare muscle injury during the first challenge.

"Rhabdomyolysis is your body saying, 'I'm going to shut down on you,'" she said of her injury, which happens when one's muscles break down. "It started with my liver, then it went to my kidneys, and then it goes to your heart. And that's where I almost died."

On Fit for TV: The Reality of The Biggest Loser, cast members claimed they were given non-approved caffeine pills, although they needed to shed pounds through diet and exercise.

"At some point, I was given stackers, and a stacker was like a caffeine pill," Cahill said.

Dr. Huizenga noted the pills broke the imposed guidelines, explaining, "Caffeine, a weight loss pill, was absolutely against everything in the show. It was in the show rules, and the patients signed off to that, and the trainers signed off to that, and all the producers signed off to that."

Season 7 contestant Joelle Gwynn described contestants' workout routine as something that was burning more calories "than maybe even the military did in a day."

"The first week, we needed to burn a minimum of 6,000 calories a day. Minimum," said Gwynn.

Cahill shared a similar comment, saying they worked out at the gym or outside for "five, six, seven, sometimes even eight hours a day."

"I don't think it's realistic for anyone to maintain that level of activity unless they're a professional athlete," Season 3 contestant Jen Kerns expressed.

During his time on The Biggest Loser, Cahill successfully lost 239 pounds in just six months, three weeks, and five days – only to gain almost all of the weight back.

"I thought I had it all figured out, and then I didn't have it all figured out," he said in the documentary.

Cahill admitted: "The shame that you feel being a failure after being a success, it's a heavy load to bear."

Although the contestants lost weight, most of them had to endure the side effects of their extreme diet and workout routines.

During the final weigh-in, Season 1 winner Ryan Benson said blood was found in his urine, which was a sign of dehydration.

"In the end, it worked out great 'cause I won, but I was doing what most doctors would say were super unhealthy things," he added. "The last 10 days, I didn't put any food in my body. I was doing the master cleanse, just drinking lemon juice and maple syrup, cayenne pepper, all these tricks that are super unhealthy just to cut weight."