Every time the Biggest Loser study (PMC4989512) gets cited someone pops up and mentions that it's been disproven but I've never seen any citation or followup. In fact, from my research I've seen lots of studies that show that there are long term metabolic changes (PMC6033771) related to adaptive thermogenesis/fat oxidization that is a fat-free mass independent effect on REE (doi: 10.3945/ajcn.115.109173).
Other studies seem to show that the lowered RMR doesn't seem to happen either doing a ketogenic diet (PMC5816424) or with ADF (PMC5042570) vs CR. I also think that the Biggest Loser results are in large part so unsuccessful due to their "crash diet" nature and the lack of any healthy habits being built for maintenance.