When it premiered in 2004, The Biggest Loser seemed like a wholesome twist on the competitive reality show formula.

Overweight contestants sharing a home competed to lose weight, with the season's "Biggest Loser" earning a cash prize. The show is meant to capture the inspirational journey the contestants take to achieve their weight loss goals. But from the very beginning audiences were skeptical that contestants could lose hundreds of pounds and keep the weight off.

It turns out we were right to wonder all along. Researchers have followed the show's contestants after they left the show and confirmed what many people guessed from the start: many of the show's contestants gain back their weight once they leave the Biggest Loser house. In fact, some have gotten even heavier over the years.

Researchers say the show's contestants, who have admitted to starving and dehydrating themselves to lose more weight during the competition, can be divided into "maintainers" and "regainers." And scientists even say that competing on the Biggest Loser makes it harder to shed the pounds in the long run.

Some of the show's most famous contestants agree...

Ryan Benson, the winner of the show's first season, lost 122 pounds during the show but later gained back as much as 140 pounds.

He revealed that in less than five days after leaving the show he gained back 32 pounds just from drinking water. While health experts say it's safest to drop just one or two pounds per week, contestants regularly drop more than 20 pounds of "water weight" in a single episode. And it turns out that has a serious effect on their body.

As a contestant loses hundreds of pounds in just a few weeks, their body's metabolism slows down to conserve weight. A study of Biggest Loser contestants found that, even years later, their metabolisms are still much slower than an average person's. That means it takes way more effort for them to lose any weight at all.

The show was canceled last year after 16 seasons, but health experts say many people are still copying the intense weight loss routines they saw on the show.

Maybe we could all learn a thing or two from season 9's winner, Michael Ventrella. He dropped from 526 pounds to 262 during the competition, then started creeping towards 300 once the cameras stopped rolling. Today, he says he focuses on his measurements, and other ways of tracking his overall health, not just the number on his scale.

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[H/T: CNN]