...Are you habitually chugging diesel fuel for lunch?
But to address your point: It seems like a disingenious and pedantic argument.
Can you come up with edge cases where my one-liner (Calories In - Calories Out) is not 100% accurate? Yes. Is that the case for the absolutely overwhelming majority of people? No. Over 70% of people in the US are overweight or obese. That's more than 2 in 3. Are we all suffering from some exotic, unknown, mysterious disturbance of the gut microbiome? Or is it more likely that we just move too little while eating too much? I think I know the answer.
Diesel fuel technically has several times as much calories as Cola-Cola. But try drinking diesel fuel for lunch and see what comes about.
This is because the human body doesn't literally burn food like in a calorimeter. Digestion is a very complex chemical reaction with lots of nuance and different nutrient pathways.