This is interesting! It’s not because they got lazy or completely fell off the nutrition wagon…apparently former biggest losers have what’s called “resting metabolism”. When you weigh so much, and then lose it, your body actually wants you to gain some of that weight back and your metabolism slows down. Who knew?!
It's a common refrain among people trying to get healthy: They lose the weight, mock their ex or celebrate, and then, by dribs and drabs, they regain the weight until they're right back where they started.