3 ms·

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.
        arcticbull 8y ago
        That's actually different, you're talking about calorie restriction (-50% of needs), what we've been discussing is fasting (0% of needs). There are substantial physiological differences between the two modes, and that study is not relevant to this conversation. Fasting actually improves your body composition (reduces proportion of fat : muscle) [5]. Further, even if you regain all the weight you lost, you'll still have a better body composition after fasting vs. CR [6]. Speculatively, even the reduced amount of food will suppress HGH production - while total abstention yields many hundreds of percent increase in levels [3, 4]. HGH is known to be responsible conserving muscle and improving body composition. It's been shown in studies that fasting raises your metabolic rate [1, 2] (again, offer not applicable to CR, by your own study and some others I don't have on hand right now). This is likely due at least in part to the production of norepinephrine during fasting. This further substantiates my point that we're talking about two different modes of operation. CR != Fasting. FWIW I agree with you, reducing your calorie consumption 50% but maintaining your 3-a-day plus snacks eating schedule is not great for you ("starvation") and likely damn hard to stick to. Weight Watchers themselves published a study that showed it just doesn't work. [7] This is what they were testing during the Minnesota starvation experiment and that didn't go well, to say the least. What my review of numerous studies indicates, is that the relationship does not extend to reducing your caloric intake 100% (obviously, intermittently for some value of intermittent). What it appears is being re-discovered is that it's not how much you eat, but what you eat, and how when/how often. [1] https://www.ncbi.nlm.nih.gov/pubmed/14066725 https://www.ncbi.nlm.nih.gov/pubmed/14066725 [2] https://www.ncbi.nlm.nih.gov/pubmed/10837292 https://www.ncbi.nlm.nih.gov/pubmed/10837292 [3] https://www.ncbi.nlm.nih.gov/pubmed/3127426 https://www.ncbi.nlm.nih.gov/pubmed/3127426 [4] https://www.ncbi.nlm.nih.gov/pubmed/1548337 https://www.ncbi.nlm.nih.gov/pubmed/1548337 [5] https://www.ncbi.nlm.nih.gov/pubmed/17413096 https://www.ncbi.nlm.nih.gov/pubmed/17413096 [6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ [7] https://fatfu.wordpress.com/2008/01/24/weight-watchers/ https://fatfu.wordpress.com/2008/01/24/weight-watchers/
  - Retric 8y ago
    PS Read that closely, muscles don't burn 10x the calories of fat, but they do burn more. Actual study demonstrating what I am saying: https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/
- erikpukinskis 8y ago
  Huh. That actually makes a lot of sense. It’s the inverse of “build muscle to burn more calories”.
- joycian 8y ago
  What is long term starvation in this context? Is a week already long term? The second point also goes against what I recall reading about cancer in calorie-restricted animals (I may be wrong). The basal metabolic rate angle is interesting, did not directly come to mind.
  - Retric 8y ago
    3 weeks at 50% calorie restriction = 5% skeletal muscle loss. This true even though it was surrounded by 3 weeks of 50% calorie surplus https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/
- arcticbull 8y ago
  That is absolutely not true. How do you plan to get food when you have the same amount of fat, and way less muscle to drag it around with? You'd be a blobby puddle until someone came to save you. That's not realistic, we'd all be so dead.
  - deleted 8y ago
    [deleted]

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.
      - arcticbull 8y ago
        That's actually different, you're talking about calorie restriction (-50% of needs), what we've been discussing is fasting (0% of needs). There are substantial physiological differences between the two modes, and that study is not relevant to this conversation. Fasting actually improves your body composition (reduces proportion of fat : muscle) [5]. Further, even if you regain all the weight you lost, you'll still have a better body composition after fasting vs. CR [6]. Speculatively, even the reduced amount of food will suppress HGH production - while total abstention yields many hundreds of percent increase in levels [3, 4]. HGH is known to be responsible conserving muscle and improving body composition. It's been shown in studies that fasting raises your metabolic rate [1, 2] (again, offer not applicable to CR, by your own study and some others I don't have on hand right now). This is likely due at least in part to the production of norepinephrine during fasting. This further substantiates my point that we're talking about two different modes of operation. CR != Fasting. FWIW I agree with you, reducing your calorie consumption 50% but maintaining your 3-a-day plus snacks eating schedule is not great for you ("starvation") and likely damn hard to stick to. Weight Watchers themselves published a study that showed it just doesn't work. [7] This is what they were testing during the Minnesota starvation experiment and that didn't go well, to say the least. What my review of numerous studies indicates, is that the relationship does not extend to reducing your caloric intake 100% (obviously, intermittently for some value of intermittent). What it appears is being re-discovered is that it's not how much you eat, but what you eat, and how when/how often. [1] https://www.ncbi.nlm.nih.gov/pubmed/14066725 https://www.ncbi.nlm.nih.gov/pubmed/14066725 [2] https://www.ncbi.nlm.nih.gov/pubmed/10837292 https://www.ncbi.nlm.nih.gov/pubmed/10837292 [3] https://www.ncbi.nlm.nih.gov/pubmed/3127426 https://www.ncbi.nlm.nih.gov/pubmed/3127426 [4] https://www.ncbi.nlm.nih.gov/pubmed/1548337 https://www.ncbi.nlm.nih.gov/pubmed/1548337 [5] https://www.ncbi.nlm.nih.gov/pubmed/17413096 https://www.ncbi.nlm.nih.gov/pubmed/17413096 [6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5042570/ [7] https://fatfu.wordpress.com/2008/01/24/weight-watchers/ https://fatfu.wordpress.com/2008/01/24/weight-watchers/
- Retric 8y ago
  PS Read that closely, muscles don't burn 10x the calories of fat, but they do burn more. Actual study demonstrating what I am saying: https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/
erikpukinskis 8y ago
Huh. That actually makes a lot of sense. It’s the inverse of “build muscle to burn more calories”.
joycian 8y ago
What is long term starvation in this context? Is a week already long term? The second point also goes against what I recall reading about cancer in calorie-restricted animals (I may be wrong). The basal metabolic rate angle is interesting, did not directly come to mind.
- Retric 8y ago
  3 weeks at 50% calorie restriction = 5% skeletal muscle loss. This true even though it was surrounded by 3 weeks of 50% calorie surplus https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/ https://www.ncbi.nlm.nih.gov/m/pubmed/26399868/
arcticbull 8y ago
That is absolutely not true. How do you plan to get food when you have the same amount of fat, and way less muscle to drag it around with? You'd be a blobby puddle until someone came to save you. That's not realistic, we'd all be so dead.
- deleted 8y ago
  [deleted]