For more than half of my life, I was quite skinny. I was not exhibiting any particularly strong willpower or self control. I never had to put forth any effort in not being fat. It was not a struggle, it was not a challenge, and it was not because I lacked a behavioral problem. Well into my 20s I had zero issue controlling my weight - though saying controlling my weight here is kind of a misnomer, since I put no thought or effort into it. If anything, when I was trying to get into powerlifting, I struggled to eat enough - I constantly felt sick trying to reach my calorie and protein targets.
Then circumstances changed. I swapped to an overnight job for more money. I started cooking less because of the hours, and eating more fast food. I stopped lifting weights because powerlifting was less interesting to me. My weight crept up little by little for years and years until I was overweight. And I realized my relationship with food had changed - ignoring physical hunger was still easy, but I was still constantly thinking about food. Slightly bored? Let's eat something. Work stressing me out? Grab some more food. Have a few minutes respite from everything? Eating sounds good. Eventually I was past overweight and into obese.
I managed to lose 30lb or so a few times, close to 50lb once. I could maintain it for a bit. But I was having to expend huge amounts of mental energy to do it - something I had never had to do before I had gotten fat in the first place. The second I had to prioritize other things in my life, for whatever reason, I no longer had the energy to spend so much time trying to push down all of the noise in my mind about food.
vs. just a decade prior, never really thinking about food at all. Is it possible for anyone to lose weight? Sure. Bodies aren't magic. Energy has to come from somewhere, and lower your calories a sufficient amount and you will lose weight. But for many people the amount of willpower and effort required is just massively different. The years of skinny me would not have lasted nearly as long as they did if I had the same level of food noise then that I do now.
No, it's not a "behavioral problem." Your phrasing is disgusting. The research is perfectly clear on why it's extrenely difficult to lose weight. There's no need for speculation.
