>>>Just read the wikipedia article on calorie. It being outside of the SI, it appears to be unregulated, so there's now the small and large calorie, so what we learn in physics as definition of kcal, is actually cal in the US. And the fine distinction, just three orders of magnitude, is lost on the casual reader of, say, dietary recommendations.
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>>Oh! Esoterica! Check out how they guess the energy for dietary recommendations. They started with an idiotic approach, and after they learned it's excrement, they stuck to the model fiddling on it. The whole branch of science is fantasy. Nothing with a real proof. Most of the experiments are guess work, to say it nice.
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>Actually, my wife almost specialized that, and she keeps telling me for years that the whole idea is bullshit. First, how they estimate the energy value of a nutrient - by burning it (how? electrically?). Then they assume that the human body can use the energy they got that way (how efficiently? 80%?), and then they estimate how much energy it needs. I remember from one of her testbooks that the necessary intake was 1600 kcal (am. cal), and 2200 was for miners and smiths. Now last I heard 2400 is for desk jobs...
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>The whole area is such a mass of guesswork, wishful thinking and eyeball estimates... and yet they claim to have the expertise to prescribe one a diet.


https://en.wikipedia.org/wiki/Calorimeter

Took the food, measured it.
After a while they learned, if you eat raw carrots, you will have no intake, but a value. So they measure, feed you a dose, try the excrements, measure those. Your intake is the difference.
Was wrong too. So they do some maths (iow guesswork). You know, maths is cheaper to alter then measurement.