Your method of measuring caloric outtake is wrong, because the body doesn't use only the calories ingested that day during that day.

I suppose so, but as long as one's caloric intake caters to cues from physiological needs (which can be co-opted by MSG and to a lesser extent HFCS and sugar alcohols, and should thus be avoided at most costs), measuring one's caloric outtake doesn't really matter so much. I'm trying, but can't see how knowing caloric outtake would be necessary when the sole criterion for calorie intake levels is physiological need, as determined by learning the cues. If one learns their average hourly caloric need at relative metabolic rest, one can judge whether they have over- or under-eated. Learning one's average heart beats per minute, and what different degrees of elevated bpm feel like, they can additionally learn by what estimate exercise increases their caloric need.

The one caveat to this, though, would be if one has imbalanced ghrelin and leptin levels - that would disable one's ability to trust their body's cues. If this condition is a concern, I think it can be tested through blood work.

However, maintaining a steady rate of metabolic activity is crucial to learning one's average caloric need per hour. Drinking cold water to just adequate levels of hydration (as judged by urine color), and consuming calories at a rate sufficient to maintain near-constant levels of digestion are of tremendous help in achieving this. I'd recommend erring on the side of unnecessarily diligent hydration (consistently clear urine) when learning what is the 'just-right' amount of hydration for one's body; learning what this amount is may take a while.

I can go into detail about why maintaining near-constant levels of digestion is helpful, but I think it might be unnecessary, and will thus abstain.

Having said that, I prefer your method to any other method I'm familiar with, perhaps even to the point of implementation.

As you may have gathered, this is essentially what I do (at the most basic level). I cannot yet accurately judge its effectiveness as a strategy, considering I may still be young enough for my naturally-high metabolism to significantly confound other variables' effects. There are also many other factors to consider, like blood sugar levels, inflammation, certain types of foods' effect on immunological processes and such processes corresponding effects upon digestion, etcetera.

In general, though, the logic should be sound. In regard to its difficulty, since becoming fluent enough with one's physiological cues takes a while, the effort expended may sum to a very high net amount of expended effort. During acclimation, however, only minimal amounts of effort would need to be expended at any one time (even less if one already has self-control/self-discipline).

In particular, adding up the numbers on the labels of the things you eat is not a sufficiently accurate method of determining caloric intake,

If that's the case, why does it work?

I agree that calorie content of any particular meal is hard to measure accurately, but over time, the calorie content of many meals should gravitate towards the average.

You're going overboard by stating, not just that CI:CO is hard, but that it's impossible.

You're saying that my positive experience with CI:CO over the past 5 years, which I was able to confirm numerous times, is a fluke.

That's you being offensive and arrogant. Yes, you should be tapping out.