Also calories are so dumb. In its most primitive form, we burn food as a proxy for metabolism. Slightly more sophisticated techniques first breakdown the food b

Also calories are so dumb. In its most primitive form, we burn food as a proxy for metabolism. Slightly more sophisticated techniques first breakdown the food by its components (sugars/fats) Calories are not just calories. That level of reduction is pseudoscience to the point where it's not really science. It's better than nothing, sure, but hair's breadth. Food is insanely complex and messy. The body's digestive chemistry is messy - a process of soups of enzymes, acids and bases. Metabolism is messy. Imagine the difference between chewing a stick of celery, a nut, drinking honey and drinking soda. Mechanically, the breakdown process of these differ wildly. Celery and nuts will be broken down very roughly. Honey is nice and viscous. Soda is lovely and runny. Now take those mechanically broken down food items and then pass them through a base bath and an acid bath and you'll unlock x% of compounds ready for metabolysis where x will differ wildly thanks also to the weird and wonderful world of solvation chemistry. THEN those compounds of varying energy richness will get broken down. The "calories" of an energy dense nut really aren't the same as a fructose-laden drink