In the context of their post, the parent (as I read it) meant the operational, nutritional definition of a calorie, not the thermodynamic one.
That is, when it's claimed on a label, does it mean "this is what you get from burning it in a lab" or "this is how much usable energy as ATP it becomes" or "this is the ignition delta between mouth and feces"? The thermodynamic definition doesn't tell us that.
That is, when it's claimed on a label, does it mean "this is what you get from burning it in a lab" or "this is how much usable energy as ATP it becomes" or "this is the ignition delta between mouth and feces"? The thermodynamic definition doesn't tell us that.