When it comes to women who will pull the pin on the fat grenade, it is not always the ones you think. Sure, the woman who has a little fat around her upper arms and was able to skate by in high school not being overweight due to puberty growth masking the bad eating habits or the recently married woman who never had discipline to exercise once may be obvious cases, but I found one example I would not have expected quite recently.
This was someone in my same high school, but not someone I knew that well personally. She played sports for all 3 seasons at school and would be considered conventionally attractive by most for sure. Over a decade later, boy did she take very poor care of herself. Fat grenade pulled and all, and pretty much unrecognizable as the same person. No idea about her relationship status, and don't care. But I never would have expected someone like her to take such bad care of herself into adulthood.
With cases like hers, I suspect it is similar to those who were just having puberty mask their bad health habits, but with the worse case of no longer playing sports to keep the calorie ratio at bay. And when we factor other things like not having parents monitor eating at home, eating out a lot, and plenty of alcohol, it is no wonder some people can get so fat. I do think it is worse for women, as they are far less likely to have the introspection to improve their eating and exercise habits.