Ura Baito: Toubou Kinshi (裏バイト:逃亡禁止) is a horror manga.
https://twitter.com/Narita_MangaOne/status/1385636843878637570 according to this there's apparently also an omake that features her attempting to diet
I've found images from the omake, but unfortunately they're in webp format, which this wiki doesn't allow.
https://twitter.com/Narita_MangaOne/status/1385636843878637570 according to this there's apparently also an omake that features her attempting to diet