5 ms·

Fat vs glucose being the energy source depending on diet? Where can I find more info about this?

by git_rancher 8y ago

jon_richards 8y ago
I think that's the premise behind keto.
- TeMPOraL 8y ago
  Yes, but that works on the idea that providing no glucose to the body will make it switch to fat instead. So it's not really diet "controlling" which fuel source to use, just body using the best fuel source available, and switching to the next one when the previous one runs out.
  - therein 8y ago
    I've followed a ketogenic diet for over over six months and lost 60lbs during that time while eating a disgusting amount of protein and fat. I never felt more clear-minded than I did during the diet. Colors were enhanced and I felt like I had unlimited energy. No ups and downs in mood during the day, no "unknown crash" at the end of the day. Of course this is after the initial crash that you experience until your body figures out it needs to switch fuel. It made me realize, often when we say we are hungry and we are craving something, it's not that we are hungry, it's that we are craving carbs.
    - TeMPOraL 8y ago
      I've been on a ketogenic diet for ~half a year a few years ago. I did lose weight and didn't experience any significant negatives, though I also didn't notice any positives - no extra mind clarity or color perception or whatever. But for the main goal - losing weight - it worked for me well.
      - therein 8y ago
        Did you make sure you were in ketosis all throughout by using ketone strips? Back when I did it, I had two friends that did it with me. One of them got cognitive benefits like I did while the other did not. It might be that we were deficient in or sensitive to something else. In fact the energy was so boundless at the 2-week mark that we actually had a hard time falling asleep at night.
        TeMPOraL 8y ago
        I didn't. I didn't even bother looking up where I could find those strips. I just cut carbs down to almost zero, eating carbs-free + controlled, small amounts of carbs. I paid attention to stay under 20g of carbs per day. I was never really sure I was in full ketosis - I just started to follow the diet, noticed some changes in urine that may or may not indicate ketosis (I definitely didn't have the intensive smell some people describe), and tracked my weight daily. It worked well over couple of months. Actually, I found the chart I made then: https://www.dropbox.com/s/vdlgazsfjjbqkox/weight-2012.png?dl=0 https://www.dropbox.com/s/vdlgazsfjjbqkox/weight-2012.png?dl... (Measurements are blue, running average (of AFAIR a week) is green. I used the running average as an indicator of progress, to eliminate measurement noise / daily variations.) That ~8-10kg drop in 3 months is when I was on ketogenic diet. I carried it a bit longer, then I guess at some point I just decided I miss pizza too much. One permanent change this caused though, that I have to this day, is that I switched from sugar to artificial sweeteners in my tea/coffee, and always opt for sugarfree coke/pepsi instead of the regular one.
        will_brown 8y ago
        >I was never really sure I was in full ketosis Following your conversation I have a wild guess...you likely were not exercising and therein likely was. First, I’ve never meet anyone who did some form of working out/exercising who couldn’t tell if they were in ketosis (good or bad). If I am right, this may also explain the feeling of mental clarity therein experiences that you didn’t. Glucose is fuel for the brain, but fat isn’t...ketones are which are a by product of fat burning, so the more fat burning/ketones the more fuel for the brain. Interesting if you both chime in on my theory.
    - dorfsmay 8y ago
      > it's not that we are hungry, it's that we are craving carbs. No. You are hungry, not necessarily for carb or protein or fat, you're just hungry. If you wait long enough, your body will switch to burn body fat.
      - therein 8y ago
        What I meant by that was this: Even after knowing that my body has switched to primarily using ketones via Ketone Measurement Strips used on urine daily, I would find myself wanting to eat something, but once I realized all I had at home that I could eat was food full of fat and protein but not carbs, my craving would disappear or I would become disinterested. And even after eating, I could still feel that it didn't hit the right spot at satisfying my cravings. I would be really full, and really full of energy-dense food but I would still be dreaming of a slice of bread or even a sip of lemonade next to whatever dish I am eating. I realized what I craved wasn't food but that spike in blood sugar.
    - DanBC 8y ago
      Sure, but this is literally what some people using homeopathy or reiki or crystal healing say.
  - will_brown 8y ago
    >Yes, but that works on the idea that providing no glucose to the body will make it switch to fat instead. So it's not really diet "controlling" which fuel source to use I think there is just a difference in the use of "controlling" here. Fat/Glucose will always be used jointly as energy, but the idea is to "control" which is the primary fuel source. A Ketogenic diet or ketosis is part of that, still giving you a fair reading I can understand how you conclude that is not "control", though I would argue it is because I am controlling my fuel source, but to your point I am not eating whatever I want (carb/sugar heavy diet) and controlling my primary fuel source like a light switch. Separate and apart from the diet, there are other things you can do to "control" or "train" your body to burn fat as the primary fuel source. Again keto is a large part of it, but lets assume I am in ketosis and about to go for one of my runs...in short, aerobic or anaerobic. Is my body going to go for the fat or is it going to go for the available glucose which is the preferred energy source for anaerobic exercise? Also, in anaerobic exercise the muscles produce lactic acid as a by product and as anaerobic exercise can only be maintained for a short period of time, when its over and the body is recovering the lactic acid goes to the liver and is converted into glucose, of course that raises the blood glucose level which in turn may encourage the body to use as the primary fuel source. Keeping my run aerobic I am "controlling" the primary fuel source and burning fat, both in the short term (same run) and long term (over periods of time) I am training my body to be pushed harder and harder while maintaining my aerobic threshold increases.
    - stefan_ 8y ago
      Deriving energy from fat is strictly less oxygen efficient than from glycogen; oxygen supply of course being the main limiter of aerobic endurance. This is why as you increase intensity towards VO2max the balance of fat versus glycogen use shifts dramatically in favor of glycogen. So training in a glycogen depleted state (back then we called this bonking) is bad news if you want to increase your aerobic threshold, since the kind of training that has been shown most effective in causing the required adaptations involves repeated maximal efforts. The only training effect you can hope for is nudging your body towards using more fat at lower levels of exertion, thereby saving valuable glycogen. This isn't very relevant for most running events which are typically done at a consistently high VO2max percentage, but beneficial for say cycling races where you have low intensity (riding in the slipstream on the flat) mixed with very high intensity (up a steep grade).
z3t4 8y ago
If I recall correctly there are some conditions where diet will have such effects, but they depend on genetics and random bad luck. So I call mostly bullshit. The body will not burn muscle, at least in a healthy human, unless near death due to starvation. The body can however adapt to what you eat and get better at converting to energy with the help of bacteria. The muscles hold water, fuel and fat, so they will look smaller when all is depleted.
StephenCanis 8y ago
Peter Attia is a doctor who has a lot of really good and detailed information on his site. The video on the page provides a detailed look at how the body breaks down glucose and fat for energy: https://peterattiamd.com/introduction-to-superstarch-part-i/ https://peterattiamd.com/introduction-to-superstarch-part-i/
- matt-smith 8y ago
  He was also a guest on Joe Rogan’s podcast not too long ago if anyone’s interested. https://youtu.be/gP1NA5f4LfE https://youtu.be/gP1NA5f4LfE I’ve been following a keto diet for some time now and still learned a lot from Peter’s discussion with Joe.
will_brown 8y ago
Depends on your interest, if you want scientific studies or practical/anecdotal information. If you want science/studies I would start maybe with the krebs cycle/ATP, ketogenic diet, ketosis, ketones as a by-product of fat buring. Maybe mix in studies about insulin, blood sugar levels/glycemic index, glucose, glycogen, glucagon/pancreas, amino acids/liver/gluconeogenesis. For more practical/functional/anecdotal information, usually your interest will be in sports/athletic performance. You might start with more generic blogs about glucose vs fat and then work your way into blogs of individual athletes in the sport you are most interested in. Although I distance run, I don't limit myself to the experiences of just other ultra runners. I also really enjoy reading about the various diets/experiences of body body builders, sprinters, other endurance sports, and mixed martial artists. It is such a wide gap in terms of performance goals and mass/muscle/weight goals.
- simsla 8y ago
  I tried to look up studies regarding ketogenesis, but most of it was pretty flimsy.
dorfsmay 8y ago
The body switches to burning fat based on insulin levels. A very bad diet can make you insulin resistant and eventually have diabetes type 2, but it is reversible. The difference between a normal person and somebody with insulin resistance is that the latter will feel hungry for longer before starting to burn fat. Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues.
- will_brown 8y ago
  >Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues. The process of converting muscle tissue into glucose falls under the umbrella of gluconeogenesis. If you burn up your glucose stores, your body may turn to fat (more efficient than converting muscle to glucose), but the body can "skip" the fat burning and turn to the break down of muscle to convert the amino acids (proteins) into glucose. Hint: its build right into your post...Insulin. If a body burns up glucose, and there are high levels of insulin in the blood, then the body will go into gluconeogenesis to breakdown muscle to convert the amino acids into glucose instead of burning fat.
  - calvano915 8y ago
    Hyperinsulinemia (https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/expert-answers/hyperinsulinemia/faq-20058488 https://www.mayoclinic.org/diseases-conditions/type-2-diabet...) is mostly prevalent among those with Type II DM (insulin resistance promoting over-production of insulin in a physiologic attempt to compensate). I don't believe all that many "normal/healthy" individuals have this issue. So while gluconeogenesis is a viable pathway for fuel, in most individuals lipid metabolism will not be skipped over for gluconeogenesis because as mentioned previously it is the slowest and least efficient pathway for ATP production. Someone with a persistent high carb and low fat diet may be in a similar state but with high demand for energy - such as the conditions described in the article - the most efficient pathways will be utilized predominantly, unless the individual went to great lengths to prevent it via their diet.
drdrey 8y ago
As usual Alex Hutchinson does a great job summarizing the research : https://www.outsideonline.com/2060591/latest-low-carb-high-fat-diets https://www.outsideonline.com/2060591/latest-low-carb-high-f... If 70% or more of your calories come from fat, your body starts increasing its fat oxidation rate, but it also down regulates the carb burning pathway
iglookid 8y ago
The following sources provide some compelling arguments for switching to intermittent fasting for many major systemic health benefits. These videos by the channel "What I've Learned" are great: - Fasting vs. Eating Less: What's the Difference? [1] - Longevity & Why I now eat One Meal a Day [2] The channel [3] also has many other videos on the topic of nutrition, with similar emphasis. Also see the excellent and readable book "The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting" by Dr Jason Fung and Jimmy Moore [4]. [1] https://youtu.be/APZCfmgzoS0 https://youtu.be/APZCfmgzoS0 [2] https://youtu.be/PKfR6bAXr-c https://youtu.be/PKfR6bAXr-c [3] https://www.youtube.com/channel/UCqYPhGiB9tkShZorfgcL2lA/videos https://www.youtube.com/channel/UCqYPhGiB9tkShZorfgcL2lA/vid... [4] https://www.amazon.com/dp/1628600012 https://www.amazon.com/dp/1628600012

Fat vs glucose being the energy source depending on diet? Where can I find more info about this?

jon_richards 8y ago

I think that's the premise behind keto.

TeMPOraL 8y ago
Yes, but that works on the idea that providing no glucose to the body will make it switch to fat instead. So it's not really diet "controlling" which fuel source to use, just body using the best fuel source available, and switching to the next one when the previous one runs out.
- therein 8y ago
  I've followed a ketogenic diet for over over six months and lost 60lbs during that time while eating a disgusting amount of protein and fat. I never felt more clear-minded than I did during the diet. Colors were enhanced and I felt like I had unlimited energy. No ups and downs in mood during the day, no "unknown crash" at the end of the day. Of course this is after the initial crash that you experience until your body figures out it needs to switch fuel. It made me realize, often when we say we are hungry and we are craving something, it's not that we are hungry, it's that we are craving carbs.
  - TeMPOraL 8y ago
    I've been on a ketogenic diet for ~half a year a few years ago. I did lose weight and didn't experience any significant negatives, though I also didn't notice any positives - no extra mind clarity or color perception or whatever. But for the main goal - losing weight - it worked for me well.
    - therein 8y ago
      Did you make sure you were in ketosis all throughout by using ketone strips? Back when I did it, I had two friends that did it with me. One of them got cognitive benefits like I did while the other did not. It might be that we were deficient in or sensitive to something else. In fact the energy was so boundless at the 2-week mark that we actually had a hard time falling asleep at night.
      - TeMPOraL 8y ago
        I didn't. I didn't even bother looking up where I could find those strips. I just cut carbs down to almost zero, eating carbs-free + controlled, small amounts of carbs. I paid attention to stay under 20g of carbs per day. I was never really sure I was in full ketosis - I just started to follow the diet, noticed some changes in urine that may or may not indicate ketosis (I definitely didn't have the intensive smell some people describe), and tracked my weight daily. It worked well over couple of months. Actually, I found the chart I made then: https://www.dropbox.com/s/vdlgazsfjjbqkox/weight-2012.png?dl=0 https://www.dropbox.com/s/vdlgazsfjjbqkox/weight-2012.png?dl... (Measurements are blue, running average (of AFAIR a week) is green. I used the running average as an indicator of progress, to eliminate measurement noise / daily variations.) That ~8-10kg drop in 3 months is when I was on ketogenic diet. I carried it a bit longer, then I guess at some point I just decided I miss pizza too much. One permanent change this caused though, that I have to this day, is that I switched from sugar to artificial sweeteners in my tea/coffee, and always opt for sugarfree coke/pepsi instead of the regular one.
        will_brown 8y ago
        >I was never really sure I was in full ketosis Following your conversation I have a wild guess...you likely were not exercising and therein likely was. First, I’ve never meet anyone who did some form of working out/exercising who couldn’t tell if they were in ketosis (good or bad). If I am right, this may also explain the feeling of mental clarity therein experiences that you didn’t. Glucose is fuel for the brain, but fat isn’t...ketones are which are a by product of fat burning, so the more fat burning/ketones the more fuel for the brain. Interesting if you both chime in on my theory.
  - dorfsmay 8y ago
    > it's not that we are hungry, it's that we are craving carbs. No. You are hungry, not necessarily for carb or protein or fat, you're just hungry. If you wait long enough, your body will switch to burn body fat.
    - therein 8y ago
      What I meant by that was this: Even after knowing that my body has switched to primarily using ketones via Ketone Measurement Strips used on urine daily, I would find myself wanting to eat something, but once I realized all I had at home that I could eat was food full of fat and protein but not carbs, my craving would disappear or I would become disinterested. And even after eating, I could still feel that it didn't hit the right spot at satisfying my cravings. I would be really full, and really full of energy-dense food but I would still be dreaming of a slice of bread or even a sip of lemonade next to whatever dish I am eating. I realized what I craved wasn't food but that spike in blood sugar.
  - DanBC 8y ago
    Sure, but this is literally what some people using homeopathy or reiki or crystal healing say.
- will_brown 8y ago
  >Yes, but that works on the idea that providing no glucose to the body will make it switch to fat instead. So it's not really diet "controlling" which fuel source to use I think there is just a difference in the use of "controlling" here. Fat/Glucose will always be used jointly as energy, but the idea is to "control" which is the primary fuel source. A Ketogenic diet or ketosis is part of that, still giving you a fair reading I can understand how you conclude that is not "control", though I would argue it is because I am controlling my fuel source, but to your point I am not eating whatever I want (carb/sugar heavy diet) and controlling my primary fuel source like a light switch. Separate and apart from the diet, there are other things you can do to "control" or "train" your body to burn fat as the primary fuel source. Again keto is a large part of it, but lets assume I am in ketosis and about to go for one of my runs...in short, aerobic or anaerobic. Is my body going to go for the fat or is it going to go for the available glucose which is the preferred energy source for anaerobic exercise? Also, in anaerobic exercise the muscles produce lactic acid as a by product and as anaerobic exercise can only be maintained for a short period of time, when its over and the body is recovering the lactic acid goes to the liver and is converted into glucose, of course that raises the blood glucose level which in turn may encourage the body to use as the primary fuel source. Keeping my run aerobic I am "controlling" the primary fuel source and burning fat, both in the short term (same run) and long term (over periods of time) I am training my body to be pushed harder and harder while maintaining my aerobic threshold increases.
  - stefan_ 8y ago
    Deriving energy from fat is strictly less oxygen efficient than from glycogen; oxygen supply of course being the main limiter of aerobic endurance. This is why as you increase intensity towards VO2max the balance of fat versus glycogen use shifts dramatically in favor of glycogen. So training in a glycogen depleted state (back then we called this bonking) is bad news if you want to increase your aerobic threshold, since the kind of training that has been shown most effective in causing the required adaptations involves repeated maximal efforts. The only training effect you can hope for is nudging your body towards using more fat at lower levels of exertion, thereby saving valuable glycogen. This isn't very relevant for most running events which are typically done at a consistently high VO2max percentage, but beneficial for say cycling races where you have low intensity (riding in the slipstream on the flat) mixed with very high intensity (up a steep grade).

z3t4 8y ago

If I recall correctly there are some conditions where diet will have such effects, but they depend on genetics and random bad luck. So I call mostly bullshit. The body will not burn muscle, at least in a healthy human, unless near death due to starvation. The body can however adapt to what you eat and get better at converting to energy with the help of bacteria. The muscles hold water, fuel and fat, so they will look smaller when all is depleted.

StephenCanis 8y ago

Peter Attia is a doctor who has a lot of really good and detailed information on his site. The video on the page provides a detailed look at how the body breaks down glucose and fat for energy: https://peterattiamd.com/introduction-to-superstarch-part-i/ https://peterattiamd.com/introduction-to-superstarch-part-i/

matt-smith 8y ago
He was also a guest on Joe Rogan’s podcast not too long ago if anyone’s interested. https://youtu.be/gP1NA5f4LfE https://youtu.be/gP1NA5f4LfE I’ve been following a keto diet for some time now and still learned a lot from Peter’s discussion with Joe.

will_brown 8y ago

Depends on your interest, if you want scientific studies or practical/anecdotal information. If you want science/studies I would start maybe with the krebs cycle/ATP, ketogenic diet, ketosis, ketones as a by-product of fat buring. Maybe mix in studies about insulin, blood sugar levels/glycemic index, glucose, glycogen, glucagon/pancreas, amino acids/liver/gluconeogenesis. For more practical/functional/anecdotal information, usually your interest will be in sports/athletic performance. You might start with more generic blogs about glucose vs fat and then work your way into blogs of individual athletes in the sport you are most interested in. Although I distance run, I don't limit myself to the experiences of just other ultra runners. I also really enjoy reading about the various diets/experiences of body body builders, sprinters, other endurance sports, and mixed martial artists. It is such a wide gap in terms of performance goals and mass/muscle/weight goals.

simsla 8y ago
I tried to look up studies regarding ketogenesis, but most of it was pretty flimsy.

dorfsmay 8y ago

The body switches to burning fat based on insulin levels. A very bad diet can make you insulin resistant and eventually have diabetes type 2, but it is reversible. The difference between a normal person and somebody with insulin resistance is that the latter will feel hungry for longer before starting to burn fat. Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues.

will_brown 8y ago
>Contrary to what the GP says, you need to be low on fat (think extremely skinny) before the body starts scavenging healthy non-fat tissues. The process of converting muscle tissue into glucose falls under the umbrella of gluconeogenesis. If you burn up your glucose stores, your body may turn to fat (more efficient than converting muscle to glucose), but the body can "skip" the fat burning and turn to the break down of muscle to convert the amino acids (proteins) into glucose. Hint: its build right into your post...Insulin. If a body burns up glucose, and there are high levels of insulin in the blood, then the body will go into gluconeogenesis to breakdown muscle to convert the amino acids into glucose instead of burning fat.
- calvano915 8y ago
  Hyperinsulinemia (https://www.mayoclinic.org/diseases-conditions/type-2-diabetes/expert-answers/hyperinsulinemia/faq-20058488 https://www.mayoclinic.org/diseases-conditions/type-2-diabet...) is mostly prevalent among those with Type II DM (insulin resistance promoting over-production of insulin in a physiologic attempt to compensate). I don't believe all that many "normal/healthy" individuals have this issue. So while gluconeogenesis is a viable pathway for fuel, in most individuals lipid metabolism will not be skipped over for gluconeogenesis because as mentioned previously it is the slowest and least efficient pathway for ATP production. Someone with a persistent high carb and low fat diet may be in a similar state but with high demand for energy - such as the conditions described in the article - the most efficient pathways will be utilized predominantly, unless the individual went to great lengths to prevent it via their diet.

drdrey 8y ago

As usual Alex Hutchinson does a great job summarizing the research : https://www.outsideonline.com/2060591/latest-low-carb-high-fat-diets https://www.outsideonline.com/2060591/latest-low-carb-high-f... If 70% or more of your calories come from fat, your body starts increasing its fat oxidation rate, but it also down regulates the carb burning pathway

iglookid 8y ago

The following sources provide some compelling arguments for switching to intermittent fasting for many major systemic health benefits. These videos by the channel "What I've Learned" are great: - Fasting vs. Eating Less: What's the Difference? [1] - Longevity & Why I now eat One Meal a Day [2] The channel [3] also has many other videos on the topic of nutrition, with similar emphasis. Also see the excellent and readable book "The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting" by Dr Jason Fung and Jimmy Moore [4]. [1] https://youtu.be/APZCfmgzoS0 https://youtu.be/APZCfmgzoS0 [2] https://youtu.be/PKfR6bAXr-c https://youtu.be/PKfR6bAXr-c [3] https://www.youtube.com/channel/UCqYPhGiB9tkShZorfgcL2lA/videos https://www.youtube.com/channel/UCqYPhGiB9tkShZorfgcL2lA/vid... [4] https://www.amazon.com/dp/1628600012 https://www.amazon.com/dp/1628600012