Neither your comment nor your parent comment add anything except noise to this discussion.
Weight, health, and fitness are all _correlated_, but sometimes in ways that aren’t intuitive and that western society’s fat-shaming (of which the “just eat less” mantra is a prime example) completely misses the point.
That said, we are not adding noise. We are giving the physics level truth. It's like being told an answer, and being told to show the proof, in my opinion. The answer is to eat less calories, but working the problem isn't so simple. There are a ton of variables into how or why someone can't follow this regime, some valid, some probably not.
Starvation mode is vastly overstated.
I wonder why people in starving nations don't have this magical starvation mode, or glandular problems, or microbiomes that make them fat. Are we exceptional?