It's analogous to weight-loss arguments.
It is true that calories = calories-in - calories-out.
It cannot not be true.
It just isn't helpful.
It is true that calories = calories-in - calories-out.
It cannot not be true.
It just isn't helpful.
tl;dr: The only time CI-CO is truly accurate is when CI=0.
For instance, in a study of obese women, a reduction of (4.3 +-(4.6) kcal/kg) was observed in a calorie restriction diet of 20kcal/kg
Similarly, in a different study, a 30% calorie intake reduction was linked to only about a 5% reduction in total energy expenditure.
CI-CO is not a perfect model, in that it doesn't perfectly estimate weight loss rates, but the general concept holds true.
I didn't mean to imply that it was 1:1, just that the model doesn't hold entirely.
> CI-CO is not a perfect model, in that it doesn't perfectly estimate weight loss rates, but the general concept holds true.
In general, I suppose, however most people aren't trying to lose weight but rather fat. Consuming sugar causes a spike in insulin, and insulin triggers the uptake of sugar in the blood by adipose tissue as fat, and actively prevents the release of fats stored therein. [1]
So in the most literal sense, CI-CO works, in that (net of the 16% reduction in TEE relative to your reduction in CI per your data) you're going to need to get the calories from somewhere. However, if you eat 30% less calories than your BMR entirely as sugar, you're much more likely to be burning alcohol, glycogen and protein than fat, certainly in the near term.
If you combine that with the "eat 6 meals per day" fad and you're in for a seriously tough time losing fat. On the other hand if you at 30% less calories than your BMR entirely as sugar in one sitting over 20 minutes and fasted the remaining 23h30 you may actually lose fat, since that'll give your body time with low insulin levels.
Let me re-state: CI-CO is a very inadequate model for losing fat.
[1] https://www.diabetes.co.uk/news/2018/jan/drop-in-both-insuli...
CI-CO is accurate if CI<CO. There is absolutely no way it cannot be. This doesn't depend on any kind of reasoning about biology or insulin or hormones at all. It's the law of conservation of energy.
That's the beauty of it. It always works. If CO<CI, you will lose weight. There has never been an exception to this in the history of life, and there never will be.
Even fasting, which you mentioned, only works as a means to an end. And that end is CI<CO. Research shows that the actual timing of fasts is irrelevant; the same calories eaten in 6 hours per day have the same effect if eaten over 16 hours of the day. But when people fast they tend to eat less overall; it's all that matters.
So many people try to follow your path, and figure out a way to manipulate complex metabolic systems they don't understand to try to wheedle the body into dropping pounds. It works only rarity, and 98% of people on this path are just deluding themselves to avoid facing the fact that they need to get CI down under CO. So they take refuge in complexity, endlessly finding ways to rationalize away the need to do the actual work.
How does calories in vs calories out work regarding the energy left in food that is not extracted (i.e. the caloric value of poop basically).
Is digestion / energy extraction pretty consistent throughout the population or do the specifics of people's digestive systems play a role in how many calories are actually available to the body?
Basically, would a constipated person's digestive tract pull more energy out of the food since it is in the intestines longer?
And even if the numbers were accurate, they're still rule-of-thumbish, because human metabolism doesn't simply ingest all energy available in a food. For instance you'd absorb roughly 40% more calories from peanut butter than from actual peanuts (of the same calorical value).
There are more reasons why counting calories isn't nearly as accurate a method as people tend to assume, but these two are really sufficient.