well, until someone comes out with more global WG/inflation art and stories, I'll throw some ideas up for y'all to enjoy
based around the concept of Life Fibers from Kill La Kill, but instead its something even less people would think were alive.
imagine 100-ish years in the future, humanity has just achieved inter-galaxy travel and now everyone on earth is having a party, food is being glorious eaten in humanity's achievement everywhere, everyone is enjoying the excess thanks to earths rising abundance in food, crops are growing like crazy, animals are so fat they produce a feast, fast food has become fast and mass produced. everyone is too excited and happy to notice that the food they're eating has turned an alluring pink color, and that now when they eat, they can't put their food down.
weeks go by and bellies start touching the floor, teens are the first to explode in size and reach the top demographic of the neo-obesity epidemic, none of them can put it down, much less thanks to exams happening, their sausage fingers get rounder and softer, their breasts make up their desks. then the men and women of the world start lazing back at the excess, barely raising a finger as they order their food automatically, barely moving to feed themselves, their hedonism only matched by the college and university students indulging themselves to calm down after a stressful study session.
eventually the whole planet is conquered by their own weight, their space travel for not as the plague of bellies reaches deep into space, humans of all kinds where getting bigger and fatter, from the moment their born to their old age they pig out over delicious food, becoming like the live stock they eagerly eat, and it's all thanks, to sugar
(alternatively, it could be something like salt or something, whatever fits your story~)