A new study is out and it's shining some light on the effects of a competitive reality show and its contestants.
Contestants like Roberto Hernandez, who learned from host Bob Harper that he had won the competition.
Biggest Loser finale - Roberto wins
Hernandez was literally half the man he was when he started the competition... but will he be able to keep the weight off?
The odds are against him.
According to this new study - most contestants not only regain many of the pounds they shed... they also have a much harder time of keeping their weight down thanks to changes in their metabolism.
With more on these findings and what they mean for a country where more than a third of Americans are obese is Michael Schwartz. He is a Professor of Medicine and the Director of the Nutrition Obesity Research Center at the University of Washington.
Is this finding a surprise?
"Actually, it wasn't surprising to me, this replicates what many other studies have shown. What seems surprising often is that the recovery of lost weight can take many years to occur as it has occurred in these contestants. And so if you look at a person one year after, it looks like they're doing great, but if you look five or more years after that's when body weight really tends to get back to where it started from."
Are some people more genetically predisposed to being obese?
"It's a complicated question...there clearly is a genetic or inherited component. Not necessarily in all cases, but in the vast majority of cases. Some of these are related to known single gene mutations, but that's rare. Probably 3% of human obesity or so can be attributed to a single gene mutation. Most of the contribution that's inherited is what we would call polygenic in the sense that there are many different genes that are contributing. And moreover, it's not that the genes are causing the obesity it's that the genes are creating a susceptibility for the individual to gain weight if it's permitted by the environment."
To hear the full interview, click the blue play button above.