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Obviously all diets have to be LIMO - Less In, More Out. Do they? What exactly does it mean? I had the impression that eating a lot of calories doesn’t mean ke

by zoul 9y ago

Obviously all diets have to be LIMO - Less In, More Out. Do they? What exactly does it mean? I had the impression that eating a lot of calories doesn’t mean keeping them – that it depends on what source they come from (fats/proteins/carbs).

LargeWu 9y ago
A calorie is a measure of engery. The laws of physics say that if you consumer fewer calories than you burn, you will lose weight, because your body needs fuel to operate. Now, your body might try to compensate and change metabolism in response to this, so that you unwittingly burn fewer calories than you consume. And yes, the types of food you're eating can affect this. But ultimately, our bodies are not perpetual motion machines, and cannot expend more energy than they take in as fuel, over the long term.
- JoeAltmaier 9y ago
  This has been a long-standing theme in this forum (HN). I've participated myself. Of course the arguments to physics are true. But they are largely irrelevant. Its not the truth that's going to help people. People eat too much, not because they don't know better (and physics! will teach them), but because they have some behavioral issue that prevents them from doing the good actions repeatedly. It always ends up here: "Just don't put the calories in your mouth. That's all you need to do." Which would be true, if food and eating were entirely volitional. But its an emotional need, a very fundamental one. Imagine saying "Just put the gun to your head and pull the trigger. That's all you need to do." While its undeniably easy, most of us, because of emotional needs to survive and avoid pain, would find it very, very hard to accomplish. (Not saying a gun-to-the-head loses weight; just comparing an easy instruction with the accompanying difficulty in performing it).
  - LargeWu 9y ago
    Oh, yeah, I totally understand that it's not useful diet advice. I have a desire to lose a few pounds, but that doesn't stop me from having a beer every night as I'm making dinner, or grabbing a piece of candy a couple of times a day while at work.
  - snowwrestler 9y ago
    It's true that bare thermodynamics is not great practical lifestyle advice, but it's also true that a lot of people really, truly, do not know the basics of what calories are and what they mean for weight. I agree that no one should use thermodynamics as an excuse to be judgmental or dismissive toward people who are having trouble managing their weight. But I also think that when people directly ask about calories (as the GP zoul did), it's worth being clear and unambiguous about the basic science.
  - Nomentatus 9y ago
    Bodies are complex. Less in More Out is only true and a matter of physics if our bodies can never refuse to absorb a calorie, or ever change gears to add tasks (such as extra DNA-repair) in times of surplus rather than always resort to mere storage. It's very unlikely that that's true. Merely altering the speed of motility through the GI tract (degree of peristalsis) alters the action of our biota and substantially changes how many calories and nutrients are available to be absorbed, as one small example.
- TheCoelacanth 9y ago
  A human body is too complex to usefully model based on such low-level physical principles. No one is going to track of how much mass they breathe in and out, how much mass they lose through sweat, excretion, urination, how much mass they eat and drink or how much energy they gain or lose through radiation. You would have to track all of those things to model weight loss based on laws of thermodynamics. If you are trying to predict weight loss based on the calorie count on the back of your food boxes and based on your level of activity, the laws of thermodynamics aren't going to be very helpful. The calorie count on the box of food is only a very rough approximation of how much usable energy your body is able to extract from the food. That amount will not be consistent for every person or even for a single person in differing scenario. "All models are wrong, but some are useful", so why be pedantic about one model being more right when it is also much less useful in the scenario and still is not a completely accurate model of reality?
  - Gibbon1 9y ago
    The best comments I've seen about this is when you look at cumulative storage needed over time to gain weigh vs the total amount of energy consumed, the 'imbalance' is an accounting error. Simple physics says one thing, simple engineering says another which is anything controlled that finely is under hormonally driven feedback control. Frankly I think in the 20th century, particularly in the US and Britain there was a strong cultural imperative to assign psychological causes for conditions medical 'science' wasn't able to explain. So fat people are gluttons, erectile dysfunction is physiological, ulcers are caused by physiological stress. Heart disease is caused by a 'type A personality'.
jdmichal 9y ago
There is some basis of merit to your line of questioning. The current caloric measurements -- 9 for a gram of fat, 4 for a gram of carbohydrates or protein -- is based on oxidation measurement. That is, how many calories are released when the food is literally burned. Then some adjustments are made to estimate the inefficiencies. For instance, dietary fiber is a carbohydrate, but it's considered to provide less energy because it's not easily digestible. However, barring inaccuracies in these numbers, once a calorie has been consumed into your body, generally the only way to get rid of it is using it. Until such a time, it will be stored as sugar or fat. https://en.wikipedia.org/wiki/Food_energy https://en.wikipedia.org/wiki/Food_energy

by zoul 9y ago

LargeWu 9y ago

A calorie is a measure of engery. The laws of physics say that if you consumer fewer calories than you burn, you will lose weight, because your body needs fuel to operate. Now, your body might try to compensate and change metabolism in response to this, so that you unwittingly burn fewer calories than you consume. And yes, the types of food you're eating can affect this. But ultimately, our bodies are not perpetual motion machines, and cannot expend more energy than they take in as fuel, over the long term.

JoeAltmaier 9y ago
This has been a long-standing theme in this forum (HN). I've participated myself. Of course the arguments to physics are true. But they are largely irrelevant. Its not the truth that's going to help people. People eat too much, not because they don't know better (and physics! will teach them), but because they have some behavioral issue that prevents them from doing the good actions repeatedly. It always ends up here: "Just don't put the calories in your mouth. That's all you need to do." Which would be true, if food and eating were entirely volitional. But its an emotional need, a very fundamental one. Imagine saying "Just put the gun to your head and pull the trigger. That's all you need to do." While its undeniably easy, most of us, because of emotional needs to survive and avoid pain, would find it very, very hard to accomplish. (Not saying a gun-to-the-head loses weight; just comparing an easy instruction with the accompanying difficulty in performing it).
- LargeWu 9y ago
  Oh, yeah, I totally understand that it's not useful diet advice. I have a desire to lose a few pounds, but that doesn't stop me from having a beer every night as I'm making dinner, or grabbing a piece of candy a couple of times a day while at work.
- snowwrestler 9y ago
  It's true that bare thermodynamics is not great practical lifestyle advice, but it's also true that a lot of people really, truly, do not know the basics of what calories are and what they mean for weight. I agree that no one should use thermodynamics as an excuse to be judgmental or dismissive toward people who are having trouble managing their weight. But I also think that when people directly ask about calories (as the GP zoul did), it's worth being clear and unambiguous about the basic science.
- Nomentatus 9y ago
  Bodies are complex. Less in More Out is only true and a matter of physics if our bodies can never refuse to absorb a calorie, or ever change gears to add tasks (such as extra DNA-repair) in times of surplus rather than always resort to mere storage. It's very unlikely that that's true. Merely altering the speed of motility through the GI tract (degree of peristalsis) alters the action of our biota and substantially changes how many calories and nutrients are available to be absorbed, as one small example.
TheCoelacanth 9y ago
A human body is too complex to usefully model based on such low-level physical principles. No one is going to track of how much mass they breathe in and out, how much mass they lose through sweat, excretion, urination, how much mass they eat and drink or how much energy they gain or lose through radiation. You would have to track all of those things to model weight loss based on laws of thermodynamics. If you are trying to predict weight loss based on the calorie count on the back of your food boxes and based on your level of activity, the laws of thermodynamics aren't going to be very helpful. The calorie count on the box of food is only a very rough approximation of how much usable energy your body is able to extract from the food. That amount will not be consistent for every person or even for a single person in differing scenario. "All models are wrong, but some are useful", so why be pedantic about one model being more right when it is also much less useful in the scenario and still is not a completely accurate model of reality?
- Gibbon1 9y ago
  The best comments I've seen about this is when you look at cumulative storage needed over time to gain weigh vs the total amount of energy consumed, the 'imbalance' is an accounting error. Simple physics says one thing, simple engineering says another which is anything controlled that finely is under hormonally driven feedback control. Frankly I think in the 20th century, particularly in the US and Britain there was a strong cultural imperative to assign psychological causes for conditions medical 'science' wasn't able to explain. So fat people are gluttons, erectile dysfunction is physiological, ulcers are caused by physiological stress. Heart disease is caused by a 'type A personality'.

jdmichal 9y ago

There is some basis of merit to your line of questioning. The current caloric measurements -- 9 for a gram of fat, 4 for a gram of carbohydrates or protein -- is based on oxidation measurement. That is, how many calories are released when the food is literally burned. Then some adjustments are made to estimate the inefficiencies. For instance, dietary fiber is a carbohydrate, but it's considered to provide less energy because it's not easily digestible. However, barring inaccuracies in these numbers, once a calorie has been consumed into your body, generally the only way to get rid of it is using it. Until such a time, it will be stored as sugar or fat. https://en.wikipedia.org/wiki/Food_energy https://en.wikipedia.org/wiki/Food_energy