I've seen a few posts discussing the long term physical and mental affects in general, but nothing specifically about the metabolic effects.
It's well known that contestants from "The Biggest Loser" typically regained all their weight after the show ended. But the cause wasn't lifestyle, it was their metabolism:
Over the following six years, the combined effects of these hormonal changes conspired to make the contestants regain much, if not all, of the weight they'd lost. But the truly shocking part was that their leptin and metabolism levels never rebounded to what they had been before the show. In fact, the more weight a contestant lost, the worse his or her slow metabolism became. This explains why weight regain was inevitable, even though they were eating less food than ever.
Alone contestants come into the show a LOT healthier than Biggest Loser contestants, but for many of them the weight loss would be as extreme, possibly worse since they're pushing their bodies into actual starvation (not to mention the pre-show bulking up).
I was wondered if any of the Alone contestants had talked about experiencing permanent changes to their metabolism after the show ended.