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This is FUD. Please cite your sources. While not healthy to literally starve yourself, getting your calories from stored fat is absolutely safe. There are doze

This is FUD. Please cite your sources. While not healthy to literally starve yourself, getting your calories from stored fat is absolutely safe. There are dozens of documented cases of people subsisting on vitimins/broth and their own fat for over a year. Proper electrolytes all but eliminate most issues you suggest, only applicable to a pure starvation diet. Conflating the 2 is either uninformed or dishonest.

consp 8y ago
In general, muscle is 'consumed' before 'fat'. Quotes since it is more complex than just what regular muscle and fatty tissues do. > While not healthy to literally starve yourself, getting your calories from stored fat is absolutely safe. No one will disagree with you there, but for most normal healthy people with regular muscle/fat content (or a bit too much) it takes a while for your body to decide it is a good idea to start creating toxins (ketones, which are quite harmless in smaller quantities) which are the result of fat conversion in a starvation diet.
- joycian 8y ago
  If that is true, then why even have fat instead of extra muscle? Burning muscle before fat makes no evolutionary sense.
  - sergiosgc 8y ago
    > If that is true, then why even have fat instead of extra muscle? Higher density, lower basal metabolic rate increase. > Burning muscle before fat makes no evolutionary sense. The chemical pathway for getting energy from muscle is much shorter than the one to get energy from fat.
    - joycian 8y ago
      So our ancestors would just die of starvation and get weaker and weaker, while keeping their fat stores?
      - Retric 8y ago
        No, but the optimum solution to survive long term starvation is to dump as much muscle mass as possible to minimize your daily calorie burn. Alongside that the body minimizes the energy spent fighting long term problems like cancer by reducing the amount of antioxidants produced etc. Some strength is still required, so their are feedback mechanisms limiting this loss. However, on a diet you are not in pure survival mode so you probably don't want to make those same sacrifices.
        nradov 8y ago
        That's a myth. Extra muscle doesn't contribute very much to resting metabolic rate. Fat isn't metabolically "free" either; it takes a lot of energy just to move adipose tissue around. https://muscleevo.net/muscle-metabolism/ https://muscleevo.net/muscle-metabolism/
        Retric 8y ago
        In starvation it's calories not pounds that's critical, also it's not a question of resting metabolic rate alone. Fat contains contains more than twice the energy per lb and every motion you do requires energy to move every lb of body weight. Net result storing energy in Fat takes ~1/3 the energy to maintain. So, sure it's not a huge difference per day. But, the difference between dying in 100 days or 100 + X days could make a huge difference.
        arcticbull 8y ago
        You're gonna need to cite some sources. Our side has studies to show you're wrong, and so far you've got nothing but your anecdotes.
        Retric 8y ago
        “Within FFM, skeletal muscle (-5%)” "Thirty-two nonobese men underwent sequential overfeeding (1 wk at +50% of energy needs), CR (3 wk at -50% of energy needs), and refeeding (2 wk at +50% of energy needs). AT and its determinants were measured together with body composition as assessed with the use of quantitative magnetic resonance, whole-body MRI, isotope dilution, and nitrogen and fluid balances." https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ So, over 6 weeks they had zero calorie deficit but even 3 weeks of starvation result cost them 5% of their skeletal muscles lower metabolic rate, and presumably increased fat. Note: Interment fasting has nothing to do with this, it takes the body several days respond to starvation a few hours don't matter as long as net calories over 2-3 days are maintained. PS: What studies? I see a linked to an article about people over estimates of mussels energy requirements not a counter argument. You’re demonstrably wrong from both experiment and basic biochemistry.
- sridca 8y ago
  > In general, muscle is 'consumed' before 'fat'. Where did you glean that information? Here's my source that contradicts your statement: https://idmprogram.com/fasting-and-muscle-mass-fasting-part-14/ https://idmprogram.com/fasting-and-muscle-mass-fasting-part-...
- irishcoffee 8y ago
  > it takes a while for your body to decide it is a good idea to start creating toxins (ketones, which are quite harmless in smaller quantities) which are the result of fat conversion in a starvation diet. Ketones are created when your body doesn't have sugar to convert into energy. This process can take as little as 12 hours, and in no way whatsoever requires a "starvation diet"
- gamblor956 8y ago
  In general, muscle is 'consumed' before 'fat'. Quotes since it is more complex than just what regular muscle and fatty tissues do. Not "in general." Only specifically in cases of starvation or caloric deficit. In general, your body burns carbs, then fat, and then muscle. Muscle is by far the least efficient energy source, so the body spares muscle in normal circumstances and only consumes muscle in times of extended caloric deficit, like fasting, starvation, marathons, etc.
  - naasking 8y ago
    > In general, your body burns carbs, then fat, and then muscle. Muscle is by far the least efficient energy source, so the body spares muscle in normal circumstances and only consumes muscle in times of extended caloric deficit This is a common belief but it's not true. You can't prevent your body from burning muscle in any kind of caloric deficit, you can only stimulate protein synthesis to counterbalance it by 1) ingesting high amounts of protein and 2) resistance training.
    - gamblor956 8y ago
      Some muscle is consumed in a state of caloric deficit, yes. But muscle isn't the body's first choice for fuel until you enter into a state of extended caloric deficit. If the opposite were true, then triathletes would consume a pound or more of muscle during their training activities and especially during competitive events, instead of burning visually significant quantities of fat.
      - naasking 8y ago
        > But muscle isn't the body's first choice for fuel until you enter into a state of extended caloric deficit. I'm honestly puzzled how people in this thread got the idea that I said that muscle was a preferred fuel. Literally no sequence of words I actually used imply this statement.
    - arcticbull 8y ago
      Yeah, sorry bud, you're just not in the right on this one. Your body always turns over muscle, sure, so some is going to be consumed. Your body produces huge quantities of HGH during starvation specifically to conserve protein and protein consumption goes down during fasting compared to steady-state. Otherwise our ancestors in periods of famine would turn into fatty puddles unable to drag themselves around. Starving means you need to get food, that's why noradrenaline levels go up, HGH production spikes (which many studies show changes your body composition to favor muscle over fat), your body switches to consuming primarily fat, and yes, some protein but not all protein is muscle. Your body also switches to producing what little glucose it actually needs via gluconeogenesis - which has many feedstocks including the glycerol backbones from triglycerides and yes, protein. But to say your body prefers to burn muscle over fat when starving is ridiculous, and just not supported by facts. [1] https://idmprogram.com/fasting-and-muscle-mass-fasting-part-14/ https://idmprogram.com/fasting-and-muscle-mass-fasting-part-...
- arcticbull 8y ago
  Ketones aren't toxins in this context, they're literally food.
tomp 8y ago
Shouldn't you cite your sources as well?
- justtopost 8y ago
  I should have, I was busy or lazy.
lukeschlather 8y ago
Here's a pretty good meta-analysis: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970209/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970209/ There's a lot of conflicting data. However I think the general thrust is that you should not try to lose weight unless you are accurately measuring how much lean mass you are losing. Otherwise it's very easy to lose a lot of muscle, which is probably not healthy unless you are extremely obese. Crucially your current body composition matters quite a lot. People under 10% body fat are going to start losing really important vital body mass. People over 25% body fat will lose mostly fat. But people have wildly different body compositions and a BMI of 25 doesn't mean 25% body fat. Again, accurate measurement is crucial. Personally, I focus on maximizing a variety of physical measurements. (How long I can hold various yoga poses without discomfort, how many situps I can do, how far I can bike/walk/swim before I begin to feel fatigued, etc.) I definitely think optimizing weight downward is a poor strategy for improved health.
- tarsinge 8y ago
  You can avoid losing muscle during a diet by doing resistance training: https://sci-fit.net/bulking-deficit-gaining/ https://sci-fit.net/bulking-deficit-gaining/
  - naasking 8y ago
    Increasing protein intake also slows lean mass loss considerably as well, even without resistance training.
always_good 8y ago
What's the difference between fasting (especially extended fasting) and "literally starving yourself"? I only hear good things about the former.
- erikpukinskis 8y ago
  Fasting has a time limit.
naasking 8y ago
> While not healthy to literally starve yourself, getting your calories from stored fat is absolutely safe. Sure, if you can guarantee that you're burning fat. That's clearly not what I said, because "weight loss" does not necessarily entail "fat loss". If all you're doing is looking at the scale, unless you take certain precautions, then you're also losing muscle mass. Doing this "quickly", which was another qualifier I stated, can be dangerous. > Proper electrolytes all but eliminate most issues you suggest, only applicable to a pure starvation diet. You need more than electrolytes to prevent muscle loss. Devoting more of your caloric budget to protein slows muscle loss considerably, and adding resistance training can prevent muscle loss entirely. But like I said, just focusing on rapid weight loss with no other considerations is dangerous.
arcticbull 8y ago
He's right, it's FUD. Studies [1] show that protein consumption goes down over the course of fasting, and that only makes sense. To borrow an analogy from [1] if your body is storing up energy for a rainy day like logs for a fire, when the power goes out are you going to chop up your axe and couch for firewood? Of course not, that's insane. Evolutionarily, it makes the most sense to conserve your muscle so you can hunt down and kill food, not waste away into a fatty blob and make it a few extra days until what, someone finds you? That's why your body's HGH production spikes to hundreds of percent of baseline, to conserve your muscles. Protein is always consumed as muscles turn over, but most tissues in your body can consume glucose OR ketones -- even your brain can switch over to consuming ketones as its primary source of energy. The remaining glucose requirements are met via gluconeogenesis, from multiple sources, including the glycerol backbone of triglycerides. However, there's plenty of non-muscle sources of protein in your body too and they are most definitely consumed as part of autophagy. [1] https://idmprogram.com/fasting-and-muscle-mass-fasting-part-14/ https://idmprogram.com/fasting-and-muscle-mass-fasting-part-...
- arcticbull 8y ago
  Re-posting my study pile for those interested: ADF succeeds in the reduction of insulin resistance/type II: https://www.ncbi.nlm.nih.gov/pubmed/15640462 https://www.ncbi.nlm.nih.gov/pubmed/15640462 Fasting increases metabolic rate: https://www.ncbi.nlm.nih.gov/pubmed/14066725 https://www.ncbi.nlm.nih.gov/pubmed/14066725 and https://www.ncbi.nlm.nih.gov/pubmed/10837292 https://www.ncbi.nlm.nih.gov/pubmed/10837292 Fasting dramatically increase HGH production: https://www.ncbi.nlm.nih.gov/pubmed/3127426 https://www.ncbi.nlm.nih.gov/pubmed/3127426 and https://www.ncbi.nlm.nih.gov/pubmed/1548337 https://www.ncbi.nlm.nih.gov/pubmed/1548337 IF (1 meal per day) improves body composition even when the caloric intake remains unchanged: https://www.ncbi.nlm.nih.gov/pubmed/17413096 https://www.ncbi.nlm.nih.gov/pubmed/17413096 Body composition is better after fasting than caloric restriction even in the event of equal amount of mass re-gain (i.e. regain after CR is fat, after ADF is muscle/lean): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ A mouse study showing ADF improves metabolic markers without change in caloric intake, but of course, it's mice, so YMMV: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872764/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872764/

consp 8y ago

In general, muscle is 'consumed' before 'fat'. Quotes since it is more complex than just what regular muscle and fatty tissues do. > While not healthy to literally starve yourself, getting your calories from stored fat is absolutely safe. No one will disagree with you there, but for most normal healthy people with regular muscle/fat content (or a bit too much) it takes a while for your body to decide it is a good idea to start creating toxins (ketones, which are quite harmless in smaller quantities) which are the result of fat conversion in a starvation diet.

joycian 8y ago
If that is true, then why even have fat instead of extra muscle? Burning muscle before fat makes no evolutionary sense.
- sergiosgc 8y ago
  > If that is true, then why even have fat instead of extra muscle? Higher density, lower basal metabolic rate increase. > Burning muscle before fat makes no evolutionary sense. The chemical pathway for getting energy from muscle is much shorter than the one to get energy from fat.
  - joycian 8y ago
    So our ancestors would just die of starvation and get weaker and weaker, while keeping their fat stores?
    - Retric 8y ago
      No, but the optimum solution to survive long term starvation is to dump as much muscle mass as possible to minimize your daily calorie burn. Alongside that the body minimizes the energy spent fighting long term problems like cancer by reducing the amount of antioxidants produced etc. Some strength is still required, so their are feedback mechanisms limiting this loss. However, on a diet you are not in pure survival mode so you probably don't want to make those same sacrifices.
      - nradov 8y ago
        That's a myth. Extra muscle doesn't contribute very much to resting metabolic rate. Fat isn't metabolically "free" either; it takes a lot of energy just to move adipose tissue around. https://muscleevo.net/muscle-metabolism/ https://muscleevo.net/muscle-metabolism/
        Retric 8y ago
        In starvation it's calories not pounds that's critical, also it's not a question of resting metabolic rate alone. Fat contains contains more than twice the energy per lb and every motion you do requires energy to move every lb of body weight. Net result storing energy in Fat takes ~1/3 the energy to maintain. So, sure it's not a huge difference per day. But, the difference between dying in 100 days or 100 + X days could make a huge difference.
        arcticbull 8y ago
        You're gonna need to cite some sources. Our side has studies to show you're wrong, and so far you've got nothing but your anecdotes.
        Retric 8y ago
        “Within FFM, skeletal muscle (-5%)” "Thirty-two nonobese men underwent sequential overfeeding (1 wk at +50% of energy needs), CR (3 wk at -50% of energy needs), and refeeding (2 wk at +50% of energy needs). AT and its determinants were measured together with body composition as assessed with the use of quantitative magnetic resonance, whole-body MRI, isotope dilution, and nitrogen and fluid balances." https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ So, over 6 weeks they had zero calorie deficit but even 3 weeks of starvation result cost them 5% of their skeletal muscles lower metabolic rate, and presumably increased fat. Note: Interment fasting has nothing to do with this, it takes the body several days respond to starvation a few hours don't matter as long as net calories over 2-3 days are maintained. PS: What studies? I see a linked to an article about people over estimates of mussels energy requirements not a counter argument. You’re demonstrably wrong from both experiment and basic biochemistry.
sridca 8y ago
> In general, muscle is 'consumed' before 'fat'. Where did you glean that information? Here's my source that contradicts your statement: https://idmprogram.com/fasting-and-muscle-mass-fasting-part-14/ https://idmprogram.com/fasting-and-muscle-mass-fasting-part-...
irishcoffee 8y ago
> it takes a while for your body to decide it is a good idea to start creating toxins (ketones, which are quite harmless in smaller quantities) which are the result of fat conversion in a starvation diet. Ketones are created when your body doesn't have sugar to convert into energy. This process can take as little as 12 hours, and in no way whatsoever requires a "starvation diet"
gamblor956 8y ago
In general, muscle is 'consumed' before 'fat'. Quotes since it is more complex than just what regular muscle and fatty tissues do. Not "in general." Only specifically in cases of starvation or caloric deficit. In general, your body burns carbs, then fat, and then muscle. Muscle is by far the least efficient energy source, so the body spares muscle in normal circumstances and only consumes muscle in times of extended caloric deficit, like fasting, starvation, marathons, etc.
- naasking 8y ago
  > In general, your body burns carbs, then fat, and then muscle. Muscle is by far the least efficient energy source, so the body spares muscle in normal circumstances and only consumes muscle in times of extended caloric deficit This is a common belief but it's not true. You can't prevent your body from burning muscle in any kind of caloric deficit, you can only stimulate protein synthesis to counterbalance it by 1) ingesting high amounts of protein and 2) resistance training.
  - gamblor956 8y ago
    Some muscle is consumed in a state of caloric deficit, yes. But muscle isn't the body's first choice for fuel until you enter into a state of extended caloric deficit. If the opposite were true, then triathletes would consume a pound or more of muscle during their training activities and especially during competitive events, instead of burning visually significant quantities of fat.
    - naasking 8y ago
      > But muscle isn't the body's first choice for fuel until you enter into a state of extended caloric deficit. I'm honestly puzzled how people in this thread got the idea that I said that muscle was a preferred fuel. Literally no sequence of words I actually used imply this statement.
  - arcticbull 8y ago
    Yeah, sorry bud, you're just not in the right on this one. Your body always turns over muscle, sure, so some is going to be consumed. Your body produces huge quantities of HGH during starvation specifically to conserve protein and protein consumption goes down during fasting compared to steady-state. Otherwise our ancestors in periods of famine would turn into fatty puddles unable to drag themselves around. Starving means you need to get food, that's why noradrenaline levels go up, HGH production spikes (which many studies show changes your body composition to favor muscle over fat), your body switches to consuming primarily fat, and yes, some protein but not all protein is muscle. Your body also switches to producing what little glucose it actually needs via gluconeogenesis - which has many feedstocks including the glycerol backbones from triglycerides and yes, protein. But to say your body prefers to burn muscle over fat when starving is ridiculous, and just not supported by facts. [1] https://idmprogram.com/fasting-and-muscle-mass-fasting-part-14/ https://idmprogram.com/fasting-and-muscle-mass-fasting-part-...
arcticbull 8y ago
Ketones aren't toxins in this context, they're literally food.

tomp 8y ago

Shouldn't you cite your sources as well?

justtopost 8y ago
I should have, I was busy or lazy.

lukeschlather 8y ago

Here's a pretty good meta-analysis: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970209/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970209/ There's a lot of conflicting data. However I think the general thrust is that you should not try to lose weight unless you are accurately measuring how much lean mass you are losing. Otherwise it's very easy to lose a lot of muscle, which is probably not healthy unless you are extremely obese. Crucially your current body composition matters quite a lot. People under 10% body fat are going to start losing really important vital body mass. People over 25% body fat will lose mostly fat. But people have wildly different body compositions and a BMI of 25 doesn't mean 25% body fat. Again, accurate measurement is crucial. Personally, I focus on maximizing a variety of physical measurements. (How long I can hold various yoga poses without discomfort, how many situps I can do, how far I can bike/walk/swim before I begin to feel fatigued, etc.) I definitely think optimizing weight downward is a poor strategy for improved health.

tarsinge 8y ago
You can avoid losing muscle during a diet by doing resistance training: https://sci-fit.net/bulking-deficit-gaining/ https://sci-fit.net/bulking-deficit-gaining/
- naasking 8y ago
  Increasing protein intake also slows lean mass loss considerably as well, even without resistance training.

always_good 8y ago

What's the difference between fasting (especially extended fasting) and "literally starving yourself"? I only hear good things about the former.

erikpukinskis 8y ago
Fasting has a time limit.

naasking 8y ago

> While not healthy to literally starve yourself, getting your calories from stored fat is absolutely safe. Sure, if you can guarantee that you're burning fat. That's clearly not what I said, because "weight loss" does not necessarily entail "fat loss". If all you're doing is looking at the scale, unless you take certain precautions, then you're also losing muscle mass. Doing this "quickly", which was another qualifier I stated, can be dangerous. > Proper electrolytes all but eliminate most issues you suggest, only applicable to a pure starvation diet. You need more than electrolytes to prevent muscle loss. Devoting more of your caloric budget to protein slows muscle loss considerably, and adding resistance training can prevent muscle loss entirely. But like I said, just focusing on rapid weight loss with no other considerations is dangerous.

arcticbull 8y ago

He's right, it's FUD. Studies [1] show that protein consumption goes down over the course of fasting, and that only makes sense. To borrow an analogy from [1] if your body is storing up energy for a rainy day like logs for a fire, when the power goes out are you going to chop up your axe and couch for firewood? Of course not, that's insane. Evolutionarily, it makes the most sense to conserve your muscle so you can hunt down and kill food, not waste away into a fatty blob and make it a few extra days until what, someone finds you? That's why your body's HGH production spikes to hundreds of percent of baseline, to conserve your muscles. Protein is always consumed as muscles turn over, but most tissues in your body can consume glucose OR ketones -- even your brain can switch over to consuming ketones as its primary source of energy. The remaining glucose requirements are met via gluconeogenesis, from multiple sources, including the glycerol backbone of triglycerides. However, there's plenty of non-muscle sources of protein in your body too and they are most definitely consumed as part of autophagy. [1] https://idmprogram.com/fasting-and-muscle-mass-fasting-part-14/ https://idmprogram.com/fasting-and-muscle-mass-fasting-part-...

arcticbull 8y ago
Re-posting my study pile for those interested: ADF succeeds in the reduction of insulin resistance/type II: https://www.ncbi.nlm.nih.gov/pubmed/15640462 https://www.ncbi.nlm.nih.gov/pubmed/15640462 Fasting increases metabolic rate: https://www.ncbi.nlm.nih.gov/pubmed/14066725 https://www.ncbi.nlm.nih.gov/pubmed/14066725 and https://www.ncbi.nlm.nih.gov/pubmed/10837292 https://www.ncbi.nlm.nih.gov/pubmed/10837292 Fasting dramatically increase HGH production: https://www.ncbi.nlm.nih.gov/pubmed/3127426 https://www.ncbi.nlm.nih.gov/pubmed/3127426 and https://www.ncbi.nlm.nih.gov/pubmed/1548337 https://www.ncbi.nlm.nih.gov/pubmed/1548337 IF (1 meal per day) improves body composition even when the caloric intake remains unchanged: https://www.ncbi.nlm.nih.gov/pubmed/17413096 https://www.ncbi.nlm.nih.gov/pubmed/17413096 Body composition is better after fasting than caloric restriction even in the event of equal amount of mass re-gain (i.e. regain after CR is fat, after ADF is muscle/lean): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ A mouse study showing ADF improves metabolic markers without change in caloric intake, but of course, it's mice, so YMMV: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872764/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5872764/