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Comment by kj01a | Hacker News Reader

>Calories in, calories out is not the golden rule, and this has been scientifically proven false.

No. If the laws of thermodynamics had been proven false, we would have heard of it.

The issue with the simplifying "calories in == calories out" is that conservation of energy is being applied over the wrong system. Our bodies are not 100% efficient at extracting energy from food, and to GP's point respond differently to different types of foods.

Thermodynamic laws certainly apply, but you just can't measure all the variables properly. Trying to apply that kind of input/output calculations on such a complicated bio-chemical model like human body is just a naive over-simplification. First you would need to calculate the caloric value of your complete excrements (including sweat), before you even know what the actual energy input is. Than you would need to measure precise oxygen used by body and the heat produced to be able to know how much of it is used by body. Not to mention that you even don't know the exact caloric values of the food that you eat. Guesstimates of this whole process that we have in a form of calorie tables and calculators are only a rough guidelines, not exact science, and that's why in real-life numbers never add up. Not because human body somehow breaks the laws of physics, but because popular calculations completely ignore a lot of biochemical nuances. How efficient is your guts in digesting different types of food, which pathway is used to turn that food into the energy and how efficiently due to levels of specific enzymes, does your body (due to the current hormonal levels) prefer to store the calories or to burn them, how efficiently you muscles are using that energy (depending on you height, weight, age, sex, health), and many, many other little details that all count.

The only problem is that calories in = calories out assumes a steady-state where there is no change in internal energy (dU/dt), which is not a good assumption.

The change in internal energy is negligible. The only exception is medical disorder.

If you want to lose weight and you are not, eat less. If the amount you eat goes below say 1200 calories and you're still not losing weight, go to a doctor.

It's that simple.

It's just not that simple, and that's the issue. And this kind of over-simplification can lead to a lot of victim blaming.

The role of sugar (especially fructose) and carbohydrate intake in obesity is very important, and there's far more to it than that.

I think it'd be a lot more challenging for someone to be obese with the same caloric amount of avocados than cheetos, for example.

When it comes to obesity the victim is to blame.

>I think it'd be a lot more challenging for someone to be obese with the same caloric amount of avocados than cheetos, for example

As I've said elsewhere, the fact that some foods are more calorie dense than other is irrelevant.

The person who does the eating is the one who gets fat, yes. But if that person is eating low quality, highly processed foods with ingredients that are far more likely to cause metabolic dysfunction, then it's not just an issue of portion size (and yes, eating too much is definitely an issue too).

And I was saying for the _same_ caloric amount, regardless of density. Never mind though, pretty clear you're a troll.

> "A calorie is a calorie" violates the second law of thermodynamics

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC506782/

That paper is defining a calorie as the chemical make up of a particular macronutrient. Which is wrong. A calorie is a unit of measure of energy.

Plus, if something violated a law of thermodynamics, that law would have changed. And it hasn't.

I probably should have added more comment, but the point is the "Calorie is a calorie" argument as applied to diet was pretty thoroughly debunked over decade ago. Calorie counting is a poor predictor of weight, while source of calories is a much stronger predictor. However, plenty of other people have commenting with more detailed explanations as to why, so I won't go on.

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