Certain ants do something like this:  https://en.wikipedia.org/wiki/Honeypot_ant The "fat" ants get inflated with food and serve as immobile storage tanks for the rest.  This behavior is indeed named and documented and...  helpful to the ants, unlike with our own fatties who are helpful to no one. And of course everybody knows about queen bees and ants and termites and such.  They get pretty huge and are fed to match.  Again, there is of course an actual beneficial purpose to the feeding and growth, unlike in overfed humans who if anything become less capable of reproduction as they grow. So yeah none of this is really what you're talking about, because it's all useful and there seems to be nothing for these creatures to be ashamed of.  Of course the non-useful overeaters in the wild world surely do just die out in most cases.  Maybe not absolutely always though?  It'd be pretty interesting to see like, some isolated island where a bunch of loser fatto shrews or something just go around eating themselves to death all the time, but still manage to scrape by because there aren't any predators around. Or even weirder:  I guess the real analogue to this BBW nonsense would be like some colony of say wild dogs that would mostly be healthy and able to hunt, except for a few giant, barely mobile bitches that got fed and protected by the rest...  for no apparent reason.  So then there could after all be predators and famines and other dangers, and the fatties would still survive well enough because the other dogs would guard them and bring them food.  But yeah scientists would be falling over themselves trying to find out why in the world they would do that.  Haha that would be a pretty famous thing I think.