American medico Kevin Hall had a pressing question after watching The Biggest Loser reality TV show: what happened to contestants’ bodies after losing all that weight in a short amount of time? So Hall and his colleagues at America’s National Institute of Diabetes used data provided by 14 former contestants over a decade to try and figure it out. The analysis suggests that contestants’ resting metabolic rate dropped after shedding the kilos quickly, and it didn’t pick up even if they gained weight or exercised. And although those who continued to exercise had more success in keeping the weight off, they saw the largest metabolic slowdown, which seems really unfair… It’s still a hypothesis, but Hall says it appears that gradual weight loss is the way to go.