Oh my sweet sweet Summer child. The retarded ideologues that created "Fat studies" do not believe obesity is a valid concept.  They believe the concept is a tool of systemic opression against Fat people by healthcare professionals, due to societal fatphobia.  They also consider "Healthism" is opression and that Fat people do not owe anyone health. ( But are totally entitled to public-funded services and ressources for their self-inflicted diseases and inability to fit places.)  And that any health problems they face is caused by Fatshaming, opression and systemic bias by doctors, nurses, paramedics...  It is entirely rooted in pseudoscience, feelz-over-realz, victimhood play-pretend.