I would slightly tweak your last. Different nutrients (vitamins/whatever) also impact your body in specific ways. Not just "makes you healthy" but "causes you

I would slightly tweak your last. Different nutrients (vitamins/whatever) also impact your body in specific ways. Not just "makes you healthy" but "causes you to do certain things." Caffeine is the easy example here. This gets back to the "feedback loops" above. There are certainly feedback loops. But you are unlikely to be able to prime any of them by just increasing an input. And increasing output is something you have to train the body to do. On that last, I think it is easy to model weight gain as something you train the body to do, as well? Certainly fits the model of the article. There are also flywheel levels of energy use for some folks. Consider the amount of calories a professional athlete goes through. We can say exercise doesn't help weight loss at the population level with relative certainty. It is also relatively safe to say exercise burns an obscene amount of calories in athletes.