“calories in calories out” still applies on the paleo diet, technically it applies to everything since it’s just a restatement of conservation of energy.
It’s just that effective diets typically reduce hunger, causing an automatic/involuntary reduction in calorie intake. Most likely by restoring the proper function of endocrine systems that are supposed to regulate hunger in response to feedback on fat mass (lipostasis).
//edit: before you guys downvote me anymore, please read about how the hypothalamus regulates energy balance and how proper regulation is disrupted in obesity:
It’s just that effective diets typically reduce hunger, causing an automatic/involuntary reduction in calorie intake.
That sort of thing is precisely why conservation of energy does not imply that calorie restriction must be an effective means of weight control. You have to know the causal relationships, not merely the correlations, even when the correlations follow from fundamental physics.
Fun anecdote: there was a period in my life, lasting several years, when I ate—had to eat—literally twice as much as I do nowadays (and I only use “literally” to mean “literally”, never “hyperbolically”). I only weighed about five pounds more. If you want to imagine where it all went, go right ahead. (Yes, there was something seriously wrong. I got better, thank you.)
Yes, but people confuse “counting calories isn’t a good strategy for losing weight” with “effective weight loss must occur by some mechanism that doesn’t involve changes in calorie intake and expenditure- such as metabolizing different foods at different efficiencies.”
I’m trying to clear up that confusion- calorie balance is critical to understand what’s going on physiologically when people lose weight, however it’s not very useful to track numerically when actually trying to lose weight.
“calories in calories out” still applies on the paleo diet, technically it applies to everything since it’s just a restatement of conservation of energy.
Sure, you can make it a scientific tautology if you like… so long as when you say “calorie” you include every kg of mass absorbed, excreted or otherwise released as 2.2 × 10^16 ‘calories’. But if you want to talk about the numbers printed on the back of the food packet under “calories” you are talking about something entirely different.
You know, the first law of thermodynamics was discovered before special relativity.
OK, we’re not interpreting “calories in calories out” that literally, but there are non-literal interpretations of it which still are very good approximation. If you interpret it to mean “it doesn’t matter to anything at all whether you eat 2000 calories of proteins or 2000 calories of sugars” it’s false, but if you interpret it to mean “the total number of calories you eat is usually way more important than where or when you get them from in determining how much weight you’ll gain or lose, provided you’re healthy enough and your diet isn’t terribly unbalanced”¹ it is essentially true, and the main idea behind The Hacker’s Diet by John Walker. ETA: And I don’t think the next order of approximation should involve lumping wholemeal rice and high-fructose corn syrup together as “carbs” and extra-virgin olive oil and hard margarine together as “fats”.
Or, more fancily, “If you e.g. eat epsilon more calories per day from fat and epsilon fewer calories per day from carbs, or epsilon fewer calories for breakfast and epsilon more calories for dinner, all other things being equal, the change in your medium-term weight-loss rate divided by epsilon will be quite small.”
I seem to recall a study finding out that people who started out weighing the same and ate the same number of calories while doing the same things did end up still weighing the same, but among them the one who ate more proteins ended up with less body fat. If I find it again I’ll post a link to it.
You know, the first law of thermodynamics was discovered before special relativity.
Fortunately scientific principles don’t rely on human awareness to function!
Or, more fancily, “If you e.g. eat epsilon more calories per day from fat and epsilon fewer calories per day from carbs, or epsilon fewer calories for breakfast and epsilon more calories for dinner, all other things being equal, the change in your medium-term weight-loss rate divided by epsilon will be quite small.”
I wouldn’t disagree with this significantly, but with the same caveat that you mention yourself.
I disagree, when people are losing weight quickly they almost invariably are eating far fewer calories. There’s some technical exceptions (such as that different nutrients are absorbed at different efficiencies, etc.) but they’re not large enough to make a huge difference in practice.
A lot of people think low carb or other weight loss diets work simply by preventing fat cells from uptaking glucose, in a low insulin environment. This is wrong, people losing weight on low carb diets are eating much less calories than they used to: if you were to force feed your old high calorie intake as fat instead if carbs, you wouldn’t lose weight. You can argue about the biochemical mechanism by which hunger is reduced but the reduced calorie intake is obvious and significant.
For the most part, calories printed on the back of a box are a good approximation of how much energy your body will actually absorb from them. It’s not something “entirely different.” Diets work mostly by reducing hunger, not by decreasing metabolic efficiency or energy absorption from food (see the link I added to my original post).
The obesity epidemic has been accompanied by a massive increase in calorie intake… however before the obesity epidemic people weren’t counting calories- they were just satisfied with less calories because their hunger was being regulated properly.
Then in as much as you yourself tried to make the claim a scientific tautology, a restatement of conservation of energy, you are plainly and trivially wrong.
Physics conserves energy as one of its fundamental properties. It so happens that humans are also good at conserving energy—and even reasonably good at treating our three main macronutrient sources as fungible—at least with respect to their use for energy production. That’s the rather impressive product of billions of years of evolution. But saying that humans are able to do this because “technically it applies to everything since it’s just a restatement of conservation of energy” is a ridiculous equivocation.
I never said or implied that humans can interchange nutrients from one form to another because of conservation of energy, there’s plenty of examples of chemical energy that the human body can’t do anything with. That isn’t related in any way to the point I am trying to make.
I don’t think I communicated clearly what I was trying to say, so I’ll restate it:
You are right that merely considering estimated calorie intake, and estimated calorie expenditure is a drastically over-simplified model of what’s going on that fails to account for many things.
However, it’s accurate enough to meaningfully model weight loss in humans. When someone switches to a paleo diet and is losing 2lb/week (as happened to me for a solid 6 months when I did), it’s not because they’re using lots of energy by some mechanism not accounted for in the over-simplified calories in/calories out model.
If you estimate food intake, you will find that a person losing 2lb/week on a paleo diet is in fact eating roughly 7000kcals a week less food than they used to.
The paleo diet doesn’t cause some metabolic condition under which the estimated calories in/calories out model is drastically inaccurate: it primarily causes overweight people to eat much less food.
I don’t think so (anymore).
“calories in calories out” still applies on the paleo diet, technically it applies to everything since it’s just a restatement of conservation of energy.
It’s just that effective diets typically reduce hunger, causing an automatic/involuntary reduction in calorie intake. Most likely by restoring the proper function of endocrine systems that are supposed to regulate hunger in response to feedback on fat mass (lipostasis).
//edit: before you guys downvote me anymore, please read about how the hypothalamus regulates energy balance and how proper regulation is disrupted in obesity:
Clinical review: Regulation of food intake, energy balance, and body fat mass: implications for the pathogenesis and treatment of obesity. Guyenet SJ, Schwartz MW J Clin Endocrinol Metab. 2012 Mar ; 97(3): 745-55
That sort of thing is precisely why conservation of energy does not imply that calorie restriction must be an effective means of weight control. You have to know the causal relationships, not merely the correlations, even when the correlations follow from fundamental physics.
Fun anecdote: there was a period in my life, lasting several years, when I ate—had to eat—literally twice as much as I do nowadays (and I only use “literally” to mean “literally”, never “hyperbolically”). I only weighed about five pounds more. If you want to imagine where it all went, go right ahead. (Yes, there was something seriously wrong. I got better, thank you.)
Yes, but people confuse “counting calories isn’t a good strategy for losing weight” with “effective weight loss must occur by some mechanism that doesn’t involve changes in calorie intake and expenditure- such as metabolizing different foods at different efficiencies.”
I’m trying to clear up that confusion- calorie balance is critical to understand what’s going on physiologically when people lose weight, however it’s not very useful to track numerically when actually trying to lose weight.
Sure, you can make it a scientific tautology if you like… so long as when you say “calorie” you include every kg of mass absorbed, excreted or otherwise released as 2.2 × 10^16 ‘calories’. But if you want to talk about the numbers printed on the back of the food packet under “calories” you are talking about something entirely different.
You know, the first law of thermodynamics was discovered before special relativity.
OK, we’re not interpreting “calories in calories out” that literally, but there are non-literal interpretations of it which still are very good approximation. If you interpret it to mean “it doesn’t matter to anything at all whether you eat 2000 calories of proteins or 2000 calories of sugars” it’s false, but if you interpret it to mean “the total number of calories you eat is usually way more important than where or when you get them from in determining how much weight you’ll gain or lose, provided you’re healthy enough and your diet isn’t terribly unbalanced”¹ it is essentially true, and the main idea behind The Hacker’s Diet by John Walker. ETA: And I don’t think the next order of approximation should involve lumping wholemeal rice and high-fructose corn syrup together as “carbs” and extra-virgin olive oil and hard margarine together as “fats”.
Or, more fancily, “If you e.g. eat epsilon more calories per day from fat and epsilon fewer calories per day from carbs, or epsilon fewer calories for breakfast and epsilon more calories for dinner, all other things being equal, the change in your medium-term weight-loss rate divided by epsilon will be quite small.”
I seem to recall a study finding out that people who started out weighing the same and ate the same number of calories while doing the same things did end up still weighing the same, but among them the one who ate more proteins ended up with less body fat. If I find it again I’ll post a link to it.
Fortunately scientific principles don’t rely on human awareness to function!
I wouldn’t disagree with this significantly, but with the same caveat that you mention yourself.
I disagree, when people are losing weight quickly they almost invariably are eating far fewer calories. There’s some technical exceptions (such as that different nutrients are absorbed at different efficiencies, etc.) but they’re not large enough to make a huge difference in practice.
A lot of people think low carb or other weight loss diets work simply by preventing fat cells from uptaking glucose, in a low insulin environment. This is wrong, people losing weight on low carb diets are eating much less calories than they used to: if you were to force feed your old high calorie intake as fat instead if carbs, you wouldn’t lose weight. You can argue about the biochemical mechanism by which hunger is reduced but the reduced calorie intake is obvious and significant.
For the most part, calories printed on the back of a box are a good approximation of how much energy your body will actually absorb from them. It’s not something “entirely different.” Diets work mostly by reducing hunger, not by decreasing metabolic efficiency or energy absorption from food (see the link I added to my original post).
The obesity epidemic has been accompanied by a massive increase in calorie intake… however before the obesity epidemic people weren’t counting calories- they were just satisfied with less calories because their hunger was being regulated properly.
Then in as much as you yourself tried to make the claim a scientific tautology, a restatement of conservation of energy, you are plainly and trivially wrong.
Physics conserves energy as one of its fundamental properties. It so happens that humans are also good at conserving energy—and even reasonably good at treating our three main macronutrient sources as fungible—at least with respect to their use for energy production. That’s the rather impressive product of billions of years of evolution. But saying that humans are able to do this because “technically it applies to everything since it’s just a restatement of conservation of energy” is a ridiculous equivocation.
I never said or implied that humans can interchange nutrients from one form to another because of conservation of energy, there’s plenty of examples of chemical energy that the human body can’t do anything with. That isn’t related in any way to the point I am trying to make.
I don’t think I communicated clearly what I was trying to say, so I’ll restate it:
You are right that merely considering estimated calorie intake, and estimated calorie expenditure is a drastically over-simplified model of what’s going on that fails to account for many things.
However, it’s accurate enough to meaningfully model weight loss in humans. When someone switches to a paleo diet and is losing 2lb/week (as happened to me for a solid 6 months when I did), it’s not because they’re using lots of energy by some mechanism not accounted for in the over-simplified calories in/calories out model.
If you estimate food intake, you will find that a person losing 2lb/week on a paleo diet is in fact eating roughly 7000kcals a week less food than they used to.
The paleo diet doesn’t cause some metabolic condition under which the estimated calories in/calories out model is drastically inaccurate: it primarily causes overweight people to eat much less food.