While this is true in individual cases, it is obviously not by any means common. Unless the human species has had some extreme mutations in the last 100 years (and only in the West). Yet this is brought up in every thread about obesity, because believing yourself to lack agency is more convenient.
The second is psychological, people whose bodies work normally and they do everything wrong on their own.
The third is structural. Countries in which a huge part of the population is obese while other similar countries don't have that problem, have systemic issues that cause that. In the US it's the fact policies all around favor food that cause obesity and make healthy food be extremely expensive, which is the opposite of what countries where obesity is uncommon do.
Fix this last issue, wait two to three generations, and you'll see obesity fall to normal levels, at which point, yes, bringing up the moral argument for some of the few remaining cases may even become valid.
Physically, that's not possible. If calories consumed is less than calories burned, the body cannot add weight. It doesn't have access to zero-point energy.
There are a plethora of conditions that cause your body and to not use energy. Whether it be physical disability that prevent movement, or diseases that dis-regulate your metabolism.
There are many people who eat sufficient food and are perpetually lethargic. Their body has the energy, and chooses not to use it.
When I did chemo, I actually put on weight, despite eating almost nothing. I had pretty bad nausea despite my 4 anti-emetics, so food was difficult to eat. Even drinking water was hard.
So how could I have possibly put on weight? Well I was sleeping 16+ hours a day, not moving at all, and my hormones plummeted. I lost most of the muscle on my body. I obviously don’t know what my basal metabolic rate was, but it must have been incredibly low. Even my brain, which uses a lot of calories, didn’t work right. I couldn’t think right.
Rather, my point was simple: calories-in and calories-out is correct, but the mistake evangelists of this ideology make is assuming calories-out is fixed or even a simple equation. It's not, and this is what pushes your narrative from "science" to "ideology".
Indeed, you said this instead:
>There are a plethora of conditions that cause your body and to not use energy
Now, grammatically it makes no sense, but I thought "and" was just a typo and then sentence read as: "There are a plethora of conditions that cause your body to not use energy" to witch I responded.
I provided some details about my specific case here:
https://news.ycombinator.com/item?id=49942780
To sum it up: my DNA is trash when it comes to this. Everything my body could do wrong, it does.
But now? You pay a very heavy price because you can very cheaply get your entire daily supply of calories in a single meal.
And don't forget, a lot of these people are set up for failure by their parents. The number of overweight children I see is staggering. These kids are almost certain to spend their lives being overweight or obese because of what their parents feed them. A drug that helps someone overcome that is a very good thing.
That's part of it. A very motivated 5' 9" person can learn to dunk a basketball, but it's a lot easier for someone who is 6' 4".
Similarly, there are probably built-in biological settings for how strongly someone feels the desire to eat.