“I’ve got my life back. I mean, I feel like a million bucks.” That was Danny Cahill after he lost an incredible amount of weight and won season eight of The Biggest Loser. But gradually, Cahill began to feel like more like 1.2 million bucks, and then 1.4 million bucks, as the pounds began to return. What was different about Cahill and the rest of the contestants on that season of the show was that they were being closely studied by scientists. And what they found is being called “frightening and amazing” by researchers in the field. As the NYT’s Gina Kolata explains: They didn’t just return to old habits. Their bodies actually fought to regain weight.