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Weight loss is not simply calories in - calories out. Fat is not burned and its metabolism does not change your weight. Oxygen/CO2 exchange in the lungs is al

by dekhn 1y ago

Weight loss is not simply calories in - calories out. Fat is not burned and its metabolism does not change your weight. Oxygen/CO2 exchange in the lungs is also a major component of weight change. Further, your body homeostatically manages your metabolism so in the long term you often return to the same weight regardless of your current calorie consumption. And that's just addressing first order weight parameters.

dgfitz 1y ago
It is calories in/out. Other mechanisms factor in, but I’ll bet anyone my bottom dollar they’ll lose weight if they eat 700 kcal/day. Yes, breathing is literally how weight is lost, I’m not sure what your point was there.
jtmarl1n 1y ago
Weight loss is absolutely a result of CICO, please site a source that states otherwise. I have never heard another source citing Oxygen/CO2 exchange as a factor for weight change, again, please site a source. O2 levels are certainly a factor of cardio health which can be correlated to overall health and weight. Yes, macros also matter. But, nothing matters as much as the simple math of calories in/calories out. Its disingenuous, borderline irresponsible, to suggest otherwise.
- SpicyLemonZest 1y ago
  https://www.bmj.com/content/349/bmj.g7257 https://www.bmj.com/content/349/bmj.g7257 is one analysis of oxygen/CO2 exchange being a major component of weight loss. As the authors say, it's really a question of chemistry; the CO2 you metabolize from your fat has to go somewhere. To be clear, I think your instinctive reaction is correct. It would be extremely silly for someone to read this analysis and conclude that they'll lose weight if they learn some special breathing technique to maximize CO2 output. The point is that "calories in - calories out" as a diet strategy is the same kind of error.
  - dekhn 1y ago
    By the way, if you ever want to start a scientific argument, bring up this paper among doctors and scientists. It never fails to start a big argument that is usually concluded with "human metabolism does not violate the conservation of mass/energy" (many doctors and scientists believe that "burning fat" with oxygen causes you to lose weight directly).
- dekhn 1y ago
  "Burning" fat doesn't violate conservation of mass/energy. Instead, weight loss occurs primarily through co2/oxygen exchange that is connected to metabolism. https://www.bmj.com/content/349/bmj.g7257 https://www.bmj.com/content/349/bmj.g7257 (note I don't totally agree with this paper, and agree that if you eat almost no food, you will lose weight, and that exercise definitely seems to increase the metabolic rate and increased mass exchange in the lungs. Like I said, it's complicated). I'm not being disingenous or irresponsible- I'm describing mainstream science based on biophysical data.
  - andoando 1y ago
    I don't think its accurate to say "weight loss occurs primarily through co2/oxygen exchange". CO2 being breathed out is the just the end product of weight loss.
  - jtmarl1n 1y ago
    Thanks, I appreciate that link. I had a chance to read this today and found it very interesting. Apologies for the tone in my original comment. I misdirected work stress this morning.
meindnoch 1y ago
>your body homeostatically manages your metabolism so in the long term you often return to the same weight regardless of your current calorie consumption Then exercise more. That's how you increase the "calories out" part of the equation. Yeah, it takes willpower.
- dekhn 1y ago
  I don't disagree that increased exercise is associated with weight loss. I don't think I denied that. We're mainly disagreeing about mechanisms. Ultimately, fat metabolism does not violate the conservation of mass/energy.
- wcfields 1y ago
  > willpower I mean, sure, but if it was just willpower for everyone then we'd all speak 10 languages, play piano, be buff as hell, be emotionally stable, and no one would be an alcoholic. But we're squishy apes that are regulated by hormones and live busy messy lives with cars that are probably needing a tire rotation 3000 miles ago and putting it off a few more miles won't really hurt.
- const_cast 1y ago
  Or it doesn’t take any willpower at all. I certainly don’t have to do this, and I’m thin. I eat whatever I want, whenever I want. So why can I do that, but others can’t? It would be comforting to just say that I’m better. It would also be a lie.
  - reissbaker 1y ago
    There are generally a few answers to this. But they all boil down to: * You never used to be fat. Once you become fat, your body's homeostatic set point is permanently altered. Your body never destroys adipocytes — it only shrinks them. If you stay within some range of your current homeostatic set point, your body will either increase the size of your adipocytes, or decrease their size, depending on whether you're over- or under-consuming. But, after a certain amount of overconsumption, your body will actually create new adipocytes... And once you have them, you can never get rid of them, minus expensive and dangerous surgery. The best you can do is shrink them. But, keeping the adipocytes shrunken takes significant willpower. So basically, once you get fat, you're going to have a hard time. Pretty much the only alternative is somehow tricking your brain/gut into not getting hungry when it "should." Ozempic, etc seem to somehow allow you to not feel as hungry even when your adipocytes shrink, or at least alter your perceived set point to be more-shrunken. Bariatric surgery is similar although much more dangerous. (Liposuction actually removes adipocytes, but it's quite dangerous — and it doesn't remove visceral fat cells, which are the worst kind of fat from a health perspective.) Now, there's a separate question of "why do some people get fat initially?" And that can result from poor childhood nutrition, or genes (e.g. Samoans), or exposure to certain chemical compounds (e.g. certain psychiatric medications), or natural aging (recent research indicates middle-aged mice, and probably thus middle-aged humans, have their stem cells trigger more adipocyte production), or just lifestyle. But it's the initial weight gain that ends up trapping people into the higher homeostatic set point, which is very difficult to recover from, even with dieting and exercise, since you will need to keep yourself basically constantly hungry either by eating less or by exercising much more even after you "lost" the weight — because while you lost weight on the scale, you didn't lose adipocytes, and adipocytes do not want to be kept empty.

by dekhn 1y ago

dgfitz 1y ago

It is calories in/out. Other mechanisms factor in, but I’ll bet anyone my bottom dollar they’ll lose weight if they eat 700 kcal/day. Yes, breathing is literally how weight is lost, I’m not sure what your point was there.

jtmarl1n 1y ago

Weight loss is absolutely a result of CICO, please site a source that states otherwise. I have never heard another source citing Oxygen/CO2 exchange as a factor for weight change, again, please site a source. O2 levels are certainly a factor of cardio health which can be correlated to overall health and weight. Yes, macros also matter. But, nothing matters as much as the simple math of calories in/calories out. Its disingenuous, borderline irresponsible, to suggest otherwise.

SpicyLemonZest 1y ago
https://www.bmj.com/content/349/bmj.g7257 https://www.bmj.com/content/349/bmj.g7257 is one analysis of oxygen/CO2 exchange being a major component of weight loss. As the authors say, it's really a question of chemistry; the CO2 you metabolize from your fat has to go somewhere. To be clear, I think your instinctive reaction is correct. It would be extremely silly for someone to read this analysis and conclude that they'll lose weight if they learn some special breathing technique to maximize CO2 output. The point is that "calories in - calories out" as a diet strategy is the same kind of error.
- dekhn 1y ago
  By the way, if you ever want to start a scientific argument, bring up this paper among doctors and scientists. It never fails to start a big argument that is usually concluded with "human metabolism does not violate the conservation of mass/energy" (many doctors and scientists believe that "burning fat" with oxygen causes you to lose weight directly).
dekhn 1y ago
"Burning" fat doesn't violate conservation of mass/energy. Instead, weight loss occurs primarily through co2/oxygen exchange that is connected to metabolism. https://www.bmj.com/content/349/bmj.g7257 https://www.bmj.com/content/349/bmj.g7257 (note I don't totally agree with this paper, and agree that if you eat almost no food, you will lose weight, and that exercise definitely seems to increase the metabolic rate and increased mass exchange in the lungs. Like I said, it's complicated). I'm not being disingenous or irresponsible- I'm describing mainstream science based on biophysical data.
- andoando 1y ago
  I don't think its accurate to say "weight loss occurs primarily through co2/oxygen exchange". CO2 being breathed out is the just the end product of weight loss.
- jtmarl1n 1y ago
  Thanks, I appreciate that link. I had a chance to read this today and found it very interesting. Apologies for the tone in my original comment. I misdirected work stress this morning.

meindnoch 1y ago

>your body homeostatically manages your metabolism so in the long term you often return to the same weight regardless of your current calorie consumption Then exercise more. That's how you increase the "calories out" part of the equation. Yeah, it takes willpower.

dekhn 1y ago
I don't disagree that increased exercise is associated with weight loss. I don't think I denied that. We're mainly disagreeing about mechanisms. Ultimately, fat metabolism does not violate the conservation of mass/energy.
wcfields 1y ago
> willpower I mean, sure, but if it was just willpower for everyone then we'd all speak 10 languages, play piano, be buff as hell, be emotionally stable, and no one would be an alcoholic. But we're squishy apes that are regulated by hormones and live busy messy lives with cars that are probably needing a tire rotation 3000 miles ago and putting it off a few more miles won't really hurt.
const_cast 1y ago
Or it doesn’t take any willpower at all. I certainly don’t have to do this, and I’m thin. I eat whatever I want, whenever I want. So why can I do that, but others can’t? It would be comforting to just say that I’m better. It would also be a lie.
- reissbaker 1y ago
  There are generally a few answers to this. But they all boil down to: * You never used to be fat. Once you become fat, your body's homeostatic set point is permanently altered. Your body never destroys adipocytes — it only shrinks them. If you stay within some range of your current homeostatic set point, your body will either increase the size of your adipocytes, or decrease their size, depending on whether you're over- or under-consuming. But, after a certain amount of overconsumption, your body will actually create new adipocytes... And once you have them, you can never get rid of them, minus expensive and dangerous surgery. The best you can do is shrink them. But, keeping the adipocytes shrunken takes significant willpower. So basically, once you get fat, you're going to have a hard time. Pretty much the only alternative is somehow tricking your brain/gut into not getting hungry when it "should." Ozempic, etc seem to somehow allow you to not feel as hungry even when your adipocytes shrink, or at least alter your perceived set point to be more-shrunken. Bariatric surgery is similar although much more dangerous. (Liposuction actually removes adipocytes, but it's quite dangerous — and it doesn't remove visceral fat cells, which are the worst kind of fat from a health perspective.) Now, there's a separate question of "why do some people get fat initially?" And that can result from poor childhood nutrition, or genes (e.g. Samoans), or exposure to certain chemical compounds (e.g. certain psychiatric medications), or natural aging (recent research indicates middle-aged mice, and probably thus middle-aged humans, have their stem cells trigger more adipocyte production), or just lifestyle. But it's the initial weight gain that ends up trapping people into the higher homeostatic set point, which is very difficult to recover from, even with dieting and exercise, since you will need to keep yourself basically constantly hungry either by eating less or by exercising much more even after you "lost" the weight — because while you lost weight on the scale, you didn't lose adipocytes, and adipocytes do not want to be kept empty.