I am not fully sourced and cannot provide any citations at this time, but something tells me a deeper dive will expose my hunches as truths.
I am convinced that people are obese because they are being poisoned. Not from overeating solely. Specifically, I believe that there are many trace poisons all throughout the products being sold as 'food' and that it is causing massive levels of poisoning to occur which is just accelerated by overeating.
The fact that they include additives to make the food taste unlike its natural constituents combined with known poisons being added discretely we are getting fatter and fatter. Because fat is actually not just an energy storage mechanism. Fat is a protective barrier and provides a lipid shield to protect the body from absorbing the harmful substances.
Many animals as they get older acquire hard fat lumps and mostly these are in animals which have liver damage or kidney or some other issue because they cannot clean their blood properly and are being poisoned beyond their ability to heal.
I believe that most of all food being consumed when it is not prepared from raw ingredients is contaminated and causing the inflammation to make their bodies generate fat for protection. This in turn fuels a massive economy (since the 80's) around fixing the issue through subscriptions that do not actually address the poisoning.
No, scars are not protective mechanism. It is an organism fault to correctly restore damaged flesh. Protective mechanism in case of wound is blood curling to stop bleeding and limphocites to get rid of bacteria and dead flesh cells. As danger is mitigated, this protective mechanisms are completely disabled and everything returns to normal.
If you want this model, then the theory will sound like "poison irreversably damage body system and it began to produce fat". Slightly different comparing to what described in OP.
But it is another theory, far from "fat is a protection from poison".
PS: And PTSD does not exist.