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I am confused by this...

> We suspect this misconception is caused by the “energy in/energy out” mantra and the focus on energy production in university biochemistry courses.

I understand from the article that chemistry (Which I can't understand) tells you that it is converted on CO2.

But still. Clearly I can move because I have energy that I acquire from food. How is this wrong ?

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Their point, which I agree is fairly unclear, is that the fat is not converted to energy, it's converted to CO₂ and water. That conversion releases energy, which you then use to move, but the total mass of the process is constant (conserved).

Just to add a bit of clarification, the excess energy part of the equation is coming from the energy stored in the chemical bonds of the original molecules.

The chemical energy of the original molecules is more than the chemical energy of the resulting molecules leaving some energy to do work and to generate heat.

That release of energy does result in mass loss. e=mc^2 as everybody knows, without understanding. However the energy is fairly small, and c is already extremely large before you square it. Over an entire lifetime the mass loss is still insignificant.

It is not wrong. It just doesn't tell you anything about where the mass goes.

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