>>76713475
I'm not trolling and I know that it's only a partial explanation. The body has the ability to let calories flush straight through the digestive system without uptake. For example, keto diets show that 5-15% of calories are not utilized, due to an altered digestive process.
More, the body has mechanisms with which it consolidates fats (insulin spikes mean that processes begin internally to store fats, instead of burn them). This is seen in people who eat a lot of sugar and fruit. Ancestrally speaking, those high sugar foods were available to the ancestors Indo-European peoples only during the late summer in fall, a time where you'd want to store up fats internally as winter approached. So by doing that - or refraining - you'd be altering rates of fat storage, regardless of calories.
Another thing to think about regarding average recommended daily intake is that different bodies have different metabolic rates, so their caloric thresholds vary.
People who say "CICO" are actually saying "I don't want to have to think about this and I don't like nuance", which is self-limiting.