You hit the nail on the head with this one again. I consider myself having grown up purity culture adjacent like you, but with ridiculously conservative parents.
I can check off most of this list. I have avoided addictions but I make up for it by self sabotaging on other ways.
One more thing about thinness...
For some, once they escape the culture, some women will gain a lot of weight, especially if they are noticed by men in a way that makes them uncomfortable.
If men think you’re undesirable because you’re fat then you dont have to find a way against all that programing to tell them no and then face the potential violence from doing so. Better to avoid them altogether.
Fatness also becomes a protection of sorts. It can be an effective one while you’re going through that deconstruction phase. Let’s face it, there’s a lot of work to be done to unpack that abusive culture once you get clear.
And during that time frame, you scream vulnerability to any exploiter. Any kind of camouflage will help you avoid the unsavory and survive.