People get fat then either of these two things happen:  They realize they're disgusting (amongst everything bad about being fat) and drop the weight They realize they're disgusting but also that they won't get thin again in a week, decide it's too much effort so fuck it and they'll just give up totally on controlling their weight and eat everything in sight until they die. It's a bit like if smokers realizing that their lung are starting to get fucked up decided that they might as well smoke 100 cigs a day since they won't get athlete lungs again in a week.