Losing weight on "The Biggest Loser" isn't a guaranteed end to the battle, and the new series "The Big Fat Truth" is going to explore why.

With many former contestants putting hard-fought pounds back on, "The Biggest Loser" creator J.D. Roth decided to work on a follow-up show, People reports. In "The Big Fat Truth," he'll spend 90 days working with six of the reality series' vets on losing the weight again -- hopefully in a more sustainable way. The group collectively lost 630 lbs on the show, only to regain that and more.

One obstacle they may have to contend with is altered metabolism. A study profiled in the New York Times in May 2016 suggested that the show's weight loss techniques slowed contestants' metabolisms, making it extremely difficult to keep the weight off when they returned to their normal lives.

Roth is aware of the study and plans to address it in the series.

"Could this really be true? ... Is it your metabolism? Or is it your choices?" he said.

We'll find out more when the show premieres June 13 at 8 p.m. ET on Z Living.

[via: People]