> No, not necessarily. Several studies have shown that different people can get different amounts of energy out of the same food, depending amongst others on their gut micro biome, though stress also seems to play a role. It’s never going to be that simple.
Sure, so they just need to compute their at-rest calorie consumption differently, and from there the rest is the same.
> Conventional thermodynamics don’t work when you consider a full human, which is a very out-of-equilibrium and not-isolated system. Conservation of energy does not tell you anything about the efficiency of the energy extraction process.
This is like saying that even if you don't refuel your car it will never stop, because different cars have different mpg ratings. A human is indeed a closed system when you consider the works it outputs and the calories it ingests, unless I somehow missed a newfound capacity for photosynthesis. The fact that it might be a bit harder to compute calorie requirements than what might be naively done does not allow you to just dismiss everything else.
Sure, so they just need to compute their at-rest calorie consumption differently, and from there the rest is the same.
> Conventional thermodynamics don’t work when you consider a full human, which is a very out-of-equilibrium and not-isolated system. Conservation of energy does not tell you anything about the efficiency of the energy extraction process.
This is like saying that even if you don't refuel your car it will never stop, because different cars have different mpg ratings. A human is indeed a closed system when you consider the works it outputs and the calories it ingests, unless I somehow missed a newfound capacity for photosynthesis. The fact that it might be a bit harder to compute calorie requirements than what might be naively done does not allow you to just dismiss everything else.