[HumanOstrich]

No, "calories in, calories out" is a popular myth, usually used as a way to insult and degrade people who are overweight.

You could drink your body's caloric needs in gasoline each day, but you'd quickly find out that WHAT you consume affects your body's response too. Biology is surprisingly complex.

[00N8]

The "calories in" part is usually understood to mean "metabolically available calories from food (& drink) in a human or other animal's diet". Calories from heat, electricity, gasoline, etc., wouldn't count.

There can be some edge cases around water retention, foods an individual happens to metabolize more/less effectively than average, & practical considerations like negative-satiety foods (things like candy or beer that contain calories but end up making you more hungry after a short while). Metabolic & activity level changes are another confounding variable one might need to track. But overall the CICO model gives accurate predictions for weight change in most cases as far as I know. I pay attention to my diet & weight & it's been perfectly reliable for me (although maybe that makes me biased to think it's a better model than it really is -- sorry if that's the case)

Anyway, you'll need to provide some evidence other than a straw-man/non-sequitur about drinking gasoline if you want to convince me CICO is a "myth"

[FooBarBizBazz]

Spreading "cope" hurts other people who read it and believe. Bomb-calorimeter energy is an upper bound on what your body can extract from the food, and limiting an upper bound works.

But ok, there is a problem with "CICO": Although true, it does psychologically put "CI" and "CO" on an equal footing -- whereas 90% of your attention really needs to be on "CI". The body is very efficient; exercising doesn't burn much. It's more for the purpose of maintaining some muscle mass as you drop weight. But junk food companies like to skew perception ("balance what you drink and do") to make it seem like a Big Gulp would be ok if only you ran more. Yeah, they're happy to shame and mislead overweight people, so long as they keep buying.

[HumanOstrich]

Your body doesn't absorb all the calories you consume, nor does it expend or store as energy all the calories you absorb. Biology is complicated and CICO is a flawed and condescending oversimplification. It's like telling people "well, you know, if you eat more than you need to, you'll gain weight". Duh, not helpful.

[naming_the_user]

If you have a diet, say each week you eat X grams of meat, Y of vegetables, Z of cereals, and then next week (or for a number of weeks) you eat {X,Y,Z}1.1 or {X,Y,Z}0.9, that will have a net effect all else being equal.

There is nothing condescending about that. No-one is really claiming that all calories are equal e.g. you can replace 500 kcals of chicken with 450 kcals of olive oil and that be some sort of blockbuster great idea.

CICO does have an implicit "your diet isn't completely batshit insane" attached to it.

[s1artibartfast]

>It's like telling people "well, you know, if you eat more than you need to, you'll gain weight". Duh, not helpful.

It is a foundation to work from. Far better than believing that you can cheat thermodynamics, which is generally the alternative.

There are some fringe cases and nuances, but I have never heard of one that was relevant. Do you have a use case where deviations would matter?

Absorbed calories don't match label calories, but weight loss and gain are studied in terms of label calories, so it is irrelevant unless you are doing chemistry or particle physics.

Labels could be in terms of arbitrary moon units instead of calories and it would still be true. Weight loss is a function of moon units in and moon units out.

[blacksmith_tb]

I don't think "drink gas" is a reasonable rebuttal, better to actually provide some kind of a reference[1].

1: https://www.pbs.org/newshour/amp/health/to-lose-weight-focus...