Unfortunately you're not arguing for what you think you're arguing for. Food is not metabolized via combustion. However there is a way to measure the energy t

Unfortunately you're not arguing for what you think you're arguing for. Food is not metabolized via combustion. However there is a way to measure the energy the human body gets from food and that's to measure the amount of ATP generated by the metabolism of a single molecule of the constituent parts of that food. And it turns out this doesn't track calories very closely at all. I'm fact, fat produces nearly 2x the ATP we would expect, except in the absence of oxaloacetic acid, in which case it produces a mere 16% of the expected value, implying that utilizing OOA for things like glycogen production can force your body to burn loads of fat for the same metabolic output, completely invalidating CICO.