This is going to be a Jeremiad, not a hopeful essay. If you want the good news about fat protagonists in SFF, look at this lovely piece from Meg Elison. If you need education about fatphobia and the ways it harms fat people mentally and physically, try these episodes of Maintenance Phase on anti-fat bias, eating disorders, and the obesity epidemic.
If you are fat, stay if you need righteous anger, but please don’t make yourself read this if you need something soft right now. This essay is for thin SFF fans and creators.