The other replies to this comment are examples of what I was talking about.
Do different foods have difference metabolic properties, including variations in accessible calories? Yes.
Can we accurately measure calorie intake? Kind of. Even with a food scale, I'm not sure we get to within 10% of the "correct" calorie count because the methods for determining the calorie / lb may have issues.
Could people do weird things, like wrap food in cellophane, burnt it before eating, or even just throw it all up? Of course.
But so what? We have a real world problem here in that Americans (and others) are suffering a material degradation in quality of life due to health issues related to diet and exercise.
There are tons of optimizations possible, but they don't matter to cohort in question. For them, CICO is good enough by far. These optimizations are like trying to teach matrix math to someone who can't add--and doesn't want to learn.
Yet, I regularly see these discussions veer into the realm of these optimizations, presumably because the real problems are too hard and/or depressing.
What I am saying that CICO and nutrition labels shouldn't matter because humans aren't supposed to or need to count CICO because our biology should be assisting us to balance it out.
The fact it's not working means something's broke.
Counting calories absolutely work for weight loss. I haven't done it and reaped the benefit of it, but ultimately it wasn't sustainable for me.
My main point was that people don't want to talk about the main issue, but rather these details.
The fact that natural hunger/satiation doesn't seem to work anymore certainly counts as a main issue (and you got some off topic replies).
Thinking about "what's broken" though, I have a few hypotheses:
1. We're surrounded by supernormal stimulatants that are hijacking our brain. (While this is possible, most of the worst food was available before the recent spikes in obesity)
2. Economics: calories (in any form) used to be expensive, so only the rich could get fat. The skills required to thrive in a world that doesn't impose calorie restriction at some level are just not widespread.
3. Our internal systems can't function in a world where people get less than 1 hour of vigorous exercise a day (or even a week). It doesn't matter how little you're spending, the body expects you're going need at least, say 1500 calories and for many people that's too many.
4. Something environmental. We're awash in so many new chemicals building up in our environments and bodies, and few have been studied for their long term effects. Maybe there's something in here that's throwing off internal signals or hormones.
I believe a good way to un-break things is gaining an awareness of where the calories are coming from, together with a. lot. of moderate exercise.
The above has worked well for me, but it's no quick fix, and wouldn't sell books, tv programmes, or speaking engagements.
'Eat less, move more' is overly simplistic, it's more about how you eat less and how you move more, to help the body's set point to shift back to a healthy level.
Calories in calories out could help if you could accurately measure them. I suspect that most people can’t. But you are right, internal mechanisms regulate both hunger and activity levels.
Is this really true and known empirically? Could the body be better at accessing calories in some foods and not others?
Thought experiment: suppose I wrapped a small chocolate bar into airtight plastic, then I swallowed it. I have just swallowed 200 calories, but my body will access/process/burn 0% of it since it can't break down the plastic.
At least in this one (unrealistic) example, CICO is false.
If you are very careful about how you define “in” and “out”, to the point where it is nearly circular, and are concerned only about weight, not health, yes. It is still problematic in a number of ways, e.g.: if you just attack thr calories in side and have a relatively sedentary lifestyle, you will disproportionately lose lean body mass rather than fat, this not only is less than ideal as an end outcome, it also makes further weight loss more difficult because it reduces resting metabolic rate (and, therefore, minimum calories out) and makes it harder to do additional exercise to increase calories out.
It is likewis known empirically that, as actionable advice, its not particularly useful on its own besides those problems, for the same reason “don’t write bugs” is as advice on how to create correct software. Most serious weightoss advice incorporates CICO, but also adds layers on top dealing with the pragmatics of how to acheive that in a maintainable way (and usually also has at least some thought in how to do it in a way dealing with problems of naive CICO like those discussed above.)
It seems that nuts are harder to digest than we thought [0], and thus our bodies do not extract as much energy from them.
Also, composition of gut microbiota seems to have an effect on metabolism and obesity, at least in mice; that should not be surprising, given that gut microbiota "predigests" some nutrients for us. [1]
Some foods have inaccessible calories. Most of what we call fiber has calories but the human gut can't get to it. I'm not 100% but I think if you can't access the calories then you don't count the calories.
CICO is shorthand for something complicated. There’s nuance, sure; but, most people could do with dropping the fork. Not always, but first measure of business should be to drop the fork and CICO until proven otherwise.
The body should be able to figure out how to not eat in excess.
It's absolutely true that if you count calories, you can manage the input such that you lose weight. But it is not a solution for the vast majority of humanity.
> The body should be able to figure out how to not eat in excess.
Why? Evolutionarily, we've had very little time where constant surplus was the norm, and mostly are adapted to situations where surpluses are rare and temporary abd shortages common.
Fighting that is hard.
Sure, our bodies might become good at that if we survive for another million years with first world standards of living as the norm. But they aren’t now, for good—evolutionary—reasons.
Except that humans don't manage their diet by counting calories. We have regulatory mechanism that supposed to do the calories counting for us.