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Can someone explain why ketosis is the secondary energy system in the body and not the primary?

by iand 6y ago

kesor 6y ago
Because most people in modern society eat way too much carb, which makes glycogen the more bio available fuel and thus being the fuel that majority of humans use in modern times. It has not always been like this. And this state is not optimal, as the various diseases and illnesses caused by metabolic syndrome, that is caused by this overload of carbs, is a major problem for the health and well being of most of these people.
lifty 6y ago
Most probably because fats were not as common as carbs were when our metabolic system evolved.
- keymone 6y ago
  carbs weren't very common: wheat, rice and potatoes literally didn't exist, fruit were nothing like they are today (probably 5% carb content). all those frutarian theories are just crazy. animals (fat and protein), on the other hand, were everywhere.
dazag 6y ago
It is the primary energy system. When a woman get pregnat, weeks before giving birth, she starts to produce ketones for the baby (it doesn't matter how many sugar the mum takes). And when the baby is born, meanwhile he drinks from mum milk he is in ketosis, because more than 50% of human milk is saturated fats. So yeah, we are in ketosis until we start to eat "food" high in carbs. The body can't burn fats if insuline is in your blood.
- shlant 6y ago
  > "It is the primary energy system" No, it's not [1]. Why do you think many organs[2] including the brain[3] that NEEDS glucose to run? > "we are in ketosis until we start to eat "food" high in carbs" No, that's not how that works. Infants are in a MILD ketosis and "this isn’t a function of their diet, but of the developmental period they’re in"[4] 1. https://academic.oup.com/ajcn/article-abstract/59/3/682S/4732269 https://academic.oup.com/ajcn/article-abstract/59/3/682S/473... 2. https://www.ncbi.nlm.nih.gov/books/NBK22436/ https://www.ncbi.nlm.nih.gov/books/NBK22436/ 3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900881/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900881/ 4. https://www.stopbeingconfusedabouthealth.com/ketogenic-diet-myth-babies-in-ketosis/ https://www.stopbeingconfusedabouthealth.com/ketogenic-diet-...
  - throwaway_kufu 6y ago
    The brain doesn’t only run on glucose it certainly runs on ketones and ketones are much more efficient at crossing the blood brain barrier. Now when the brain is running off ketones it still needs some glucose, but the body accounts for that by being able to produce its own glucose and doesn’t need it from outside sources like carbs or sugar). Ketosis is the default energy System, in that all things being equal when a person doesn’t introduce any food they naturally go into ketosis. People literally need to eat certain foods that spike insulin to get “kicked out” of ketosis.
    - shlant 6y ago
      > ketones are much more efficient at crossing the blood brain barrier Source? > Ketosis is the default energy System, in that all things being equal when a person doesn’t introduce any food they naturally go into ketosis. People literally need to eat certain foods that spike insulin to get “kicked out” of ketosis. That is not a sound argument for it being the "default energy system". It makes much more sense that "default energy system" is that which directly provides the energy source REQUIRED by the brain[1]. Additionally, our closest ancestors (primates) were frugavorian omnivores. Ketosis is a state of starvation and the long term complications from it support that[2] but I guess starvation could be argued to be the "default state" of all living things. 1. https://www.ncbi.nlm.nih.gov/books/NBK28048/ https://www.ncbi.nlm.nih.gov/books/NBK28048/ 2. https://www.thepaleomom.com/adverse-reactions-to-ketogenic-diets-caution-advised/ https://www.thepaleomom.com/adverse-reactions-to-ketogenic-d...
      - PudgePacket 6y ago
        Humans can produce all the glucose they need when in nutritional ketosis or starvation ketosis. https://en.wikipedia.org/wiki/Gluconeogenesis https://en.wikipedia.org/wiki/Gluconeogenesis
        shlant 6y ago
        but does that make it the "default energy System"?
- KMag 6y ago
  I think you mean 50% of the calories in human milk comes from saturated fats, not that the milk itself is 50% (by mass?) saturated fats.
faichai 6y ago
Related to this, what do dogs and other carnivores use? Are they always running on ketones?
mrob 6y ago
Probably because we can store far more fats than we can carbs. It makes sense to use the carbs first because that avoids the need to convert them to fats so they aren't wasted.
cies 6y ago
Our bodies are primate bodies. Primates are frugavorian omnivores (get most calories from fruit, and eat very little animal tissue (mostly insects)). Fruit contain mostly carbs: short carbs a.k.a. sugars. We're optimized for eating lots of sugar. Primates have a hard time producing fat from carbs (a process called lipogenesis), just a few calorie% per day. This, combined with the tiny bits of fat in fruits/insects, we may store as fat tissue. Here comes ketosis: when we cannot find adequate food supply (starve) we can live off our fat storage, this is what ketosis is for (biologically/evolutionary). It's our starvation mode. Primates are not made to be in ketosis for long times. We're also not made to eat high fat and/or high protein diets. We're made for a high fruit diet. Is long term ketosis bad? I believe so, but we still need to do research on this. Many people are trying it on themselves lately, so we will soon know. Is short term keto dieting bad? Nope. And it may help you to burn that body fat fast. I'd prefer to get into keto by mimicking starvation, a.k.a. (intermittent) fasting, and not by eating lots of fat/protein. Is eating lots of animal products bad for you? Yes. It's been shown again and again in large studies that humans do better on predominantly whole plant foods.
- reedf1 6y ago
  I agree with a lot of what you said - I mean this with the highest degree of respect - but I've noticed a certain strain of assertions here that throws off alarm bells. Do you have some resources on this "frugavorian" thing?
  - shlant 6y ago
    here's some information to start with: https://link.springer.com/chapter/10.1007/978-1-4020-9699-0_1 https://link.springer.com/chapter/10.1007/978-1-4020-9699-0_... Here is a simplified overview: https://steemitimages.com/DQmYgdPbWvCt78oycPdEKNffevjh7UnCsqWRDtVxFJvtNXd/comparative%20anatomy%20vegan.jpg https://steemitimages.com/DQmYgdPbWvCt78oycPdEKNffevjh7UnCsq...
    - amanaplanacanal 6y ago
      “Nonhuman” primates, it says. It’s pretty clear that humans haven’t eaten a primarily fruit based diet in a very long time. It’s likely that moving away from that diet predated changes that made us human.
StacyC 6y ago
My understanding of this is that the body will always preferentially burn glucose because excess blood sugar is highly problematic, while excess fat can just be stored without the severe health risk. With carb intake reduced the body will naturally switch to burning fat because it is the only fuel source available.
throwaway_kufu 6y ago
Keto is the primary energy system. Consider when you don’t eat (fasting) your body goes into Ketosis. In other words it’s the default energy system. You literally have to introduce Specific foods that knock you out of Ketosis...it just so happens now a days those are the primary foods people eat. Foods that spike insulin and knock you out of Ketosis really wouldn’t have been available in a constant supply to keep people running on glucose pre-agriculture. Also consider the blood brain barrier, ketones are much more efficient at crossing the blood brain barrier to fuel the brain compared to glucose.
- mrob 6y ago
  Even in the environment of evolutionary adaptedness, prolonged fasting is not the default. If you're going to argue that metabolism under abnormal conditions defines the primary energy system, alcohol must be the primary energy system. It's used at higher priority than either carbs or fats.
  - throwaway_kufu 6y ago
    Alcohol is an energy source just as much as carbs, fat and protein for sure...but the brain can’t run on alcohol, only ketones and glucose. Your natural state is ketosis (that makes it the primary fuel source). And we are not talking about “prolonged fasting” or “abnormal conditions”, we are talking about natural states. So if you happen to kick yourself out of ketosis and start running primarily on glucose most people will burn through their glucose stores in just a few hours and their body will crash/shutdown to preserve the remaining glucose for the brain (think of marathon runners “hitting the wall” which doesn’t happen in ketosis, you basically have unlimited fat energy stores and your body will internally produce the limited glucose the brain needs)

Can someone explain why ketosis is the secondary energy system in the body and not the primary?

by iand 6y ago

Can someone explain why ketosis is the secondary energy system in the body and not the primary?

Because most people in modern society eat way too much carb, which makes glycogen the more bio available fuel and thus being the fuel that majority of humans use in modern times. It has not always been like this. And this state is not optimal, as the various diseases and illnesses caused by metabolic syndrome, that is caused by this overload of carbs, is a major problem for the health and well being of most of these people.

lifty 6y ago

Most probably because fats were not as common as carbs were when our metabolic system evolved.

keymone 6y ago
carbs weren't very common: wheat, rice and potatoes literally didn't exist, fruit were nothing like they are today (probably 5% carb content). all those frutarian theories are just crazy. animals (fat and protein), on the other hand, were everywhere.

dazag 6y ago

It is the primary energy system. When a woman get pregnat, weeks before giving birth, she starts to produce ketones for the baby (it doesn't matter how many sugar the mum takes). And when the baby is born, meanwhile he drinks from mum milk he is in ketosis, because more than 50% of human milk is saturated fats. So yeah, we are in ketosis until we start to eat "food" high in carbs. The body can't burn fats if insuline is in your blood.

shlant 6y ago
> "It is the primary energy system" No, it's not [1]. Why do you think many organs[2] including the brain[3] that NEEDS glucose to run? > "we are in ketosis until we start to eat "food" high in carbs" No, that's not how that works. Infants are in a MILD ketosis and "this isn’t a function of their diet, but of the developmental period they’re in"[4] 1. https://academic.oup.com/ajcn/article-abstract/59/3/682S/4732269 https://academic.oup.com/ajcn/article-abstract/59/3/682S/473... 2. https://www.ncbi.nlm.nih.gov/books/NBK22436/ https://www.ncbi.nlm.nih.gov/books/NBK22436/ 3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900881/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900881/ 4. https://www.stopbeingconfusedabouthealth.com/ketogenic-diet-myth-babies-in-ketosis/ https://www.stopbeingconfusedabouthealth.com/ketogenic-diet-...
- throwaway_kufu 6y ago
  The brain doesn’t only run on glucose it certainly runs on ketones and ketones are much more efficient at crossing the blood brain barrier. Now when the brain is running off ketones it still needs some glucose, but the body accounts for that by being able to produce its own glucose and doesn’t need it from outside sources like carbs or sugar). Ketosis is the default energy System, in that all things being equal when a person doesn’t introduce any food they naturally go into ketosis. People literally need to eat certain foods that spike insulin to get “kicked out” of ketosis.
  - shlant 6y ago
    > ketones are much more efficient at crossing the blood brain barrier Source? > Ketosis is the default energy System, in that all things being equal when a person doesn’t introduce any food they naturally go into ketosis. People literally need to eat certain foods that spike insulin to get “kicked out” of ketosis. That is not a sound argument for it being the "default energy system". It makes much more sense that "default energy system" is that which directly provides the energy source REQUIRED by the brain[1]. Additionally, our closest ancestors (primates) were frugavorian omnivores. Ketosis is a state of starvation and the long term complications from it support that[2] but I guess starvation could be argued to be the "default state" of all living things. 1. https://www.ncbi.nlm.nih.gov/books/NBK28048/ https://www.ncbi.nlm.nih.gov/books/NBK28048/ 2. https://www.thepaleomom.com/adverse-reactions-to-ketogenic-diets-caution-advised/ https://www.thepaleomom.com/adverse-reactions-to-ketogenic-d...
    - PudgePacket 6y ago
      Humans can produce all the glucose they need when in nutritional ketosis or starvation ketosis. https://en.wikipedia.org/wiki/Gluconeogenesis https://en.wikipedia.org/wiki/Gluconeogenesis
      - shlant 6y ago
        but does that make it the "default energy System"?
KMag 6y ago
I think you mean 50% of the calories in human milk comes from saturated fats, not that the milk itself is 50% (by mass?) saturated fats.

faichai 6y ago

Related to this, what do dogs and other carnivores use? Are they always running on ketones?

mrob 6y ago

Probably because we can store far more fats than we can carbs. It makes sense to use the carbs first because that avoids the need to convert them to fats so they aren't wasted.

cies 6y ago

Our bodies are primate bodies. Primates are frugavorian omnivores (get most calories from fruit, and eat very little animal tissue (mostly insects)). Fruit contain mostly carbs: short carbs a.k.a. sugars. We're optimized for eating lots of sugar. Primates have a hard time producing fat from carbs (a process called lipogenesis), just a few calorie% per day. This, combined with the tiny bits of fat in fruits/insects, we may store as fat tissue. Here comes ketosis: when we cannot find adequate food supply (starve) we can live off our fat storage, this is what ketosis is for (biologically/evolutionary). It's our starvation mode. Primates are not made to be in ketosis for long times. We're also not made to eat high fat and/or high protein diets. We're made for a high fruit diet. Is long term ketosis bad? I believe so, but we still need to do research on this. Many people are trying it on themselves lately, so we will soon know. Is short term keto dieting bad? Nope. And it may help you to burn that body fat fast. I'd prefer to get into keto by mimicking starvation, a.k.a. (intermittent) fasting, and not by eating lots of fat/protein. Is eating lots of animal products bad for you? Yes. It's been shown again and again in large studies that humans do better on predominantly whole plant foods.

reedf1 6y ago
I agree with a lot of what you said - I mean this with the highest degree of respect - but I've noticed a certain strain of assertions here that throws off alarm bells. Do you have some resources on this "frugavorian" thing?
- shlant 6y ago
  here's some information to start with: https://link.springer.com/chapter/10.1007/978-1-4020-9699-0_1 https://link.springer.com/chapter/10.1007/978-1-4020-9699-0_... Here is a simplified overview: https://steemitimages.com/DQmYgdPbWvCt78oycPdEKNffevjh7UnCsqWRDtVxFJvtNXd/comparative%20anatomy%20vegan.jpg https://steemitimages.com/DQmYgdPbWvCt78oycPdEKNffevjh7UnCsq...
  - amanaplanacanal 6y ago
    “Nonhuman” primates, it says. It’s pretty clear that humans haven’t eaten a primarily fruit based diet in a very long time. It’s likely that moving away from that diet predated changes that made us human.

StacyC 6y ago

My understanding of this is that the body will always preferentially burn glucose because excess blood sugar is highly problematic, while excess fat can just be stored without the severe health risk. With carb intake reduced the body will naturally switch to burning fat because it is the only fuel source available.

throwaway_kufu 6y ago

Keto is the primary energy system. Consider when you don’t eat (fasting) your body goes into Ketosis. In other words it’s the default energy system. You literally have to introduce Specific foods that knock you out of Ketosis...it just so happens now a days those are the primary foods people eat. Foods that spike insulin and knock you out of Ketosis really wouldn’t have been available in a constant supply to keep people running on glucose pre-agriculture. Also consider the blood brain barrier, ketones are much more efficient at crossing the blood brain barrier to fuel the brain compared to glucose.

mrob 6y ago
Even in the environment of evolutionary adaptedness, prolonged fasting is not the default. If you're going to argue that metabolism under abnormal conditions defines the primary energy system, alcohol must be the primary energy system. It's used at higher priority than either carbs or fats.
- throwaway_kufu 6y ago
  Alcohol is an energy source just as much as carbs, fat and protein for sure...but the brain can’t run on alcohol, only ketones and glucose. Your natural state is ketosis (that makes it the primary fuel source). And we are not talking about “prolonged fasting” or “abnormal conditions”, we are talking about natural states. So if you happen to kick yourself out of ketosis and start running primarily on glucose most people will burn through their glucose stores in just a few hours and their body will crash/shutdown to preserve the remaining glucose for the brain (think of marathon runners “hitting the wall” which doesn’t happen in ketosis, you basically have unlimited fat energy stores and your body will internally produce the limited glucose the brain needs)