This was really fantastic. I felt you read my mind when you explained why acetyl CoA is not gluconeogenic even though it "seems" like it enters the TCA cycle and makes an entire round (just like how intermediates derived from gluconeogenic amino acids can actually be gluconeogenic via oxaloacetate). So the reason acetyl CoA (and therefore fatty acids, leucine, and lysine) is not gluconeogenic is that we lose the carbons as CO2. Further, PDH is irreversible. That was awesome. A good teacher preempts her students' confusions!
Hmm, I don't think the video explains this very well. You require OAA and Acetyl-CoA to form citrate in the cycle, so if there is no net gain of OAA, then gluconeogenesis cannot occur with FFA alone.
I was almost about to get confused before I could find such an amazing video.....You have cleared all the misconception regarding the integration of all this cellular respiration series.
I have been watching a few videos on the metabolism because of my pre-disposition to diabetes. I have started a Ketogenic eating lifestyle and this really starts to bring home my understanding of the ketogenic lifestyle. BTW, I've never felt healthier since I lowered my carb intake. My energy level is awesome, I immediately lost 20 lbs and the fat around my waist. Thanks for the awesome info.
This is such a good video my goodness. This information is a must for those learning biochem and want to know the overall purpose of these starvation processes.
I have been struggling with the whole process of ketone production and use in Kreb's cycle but this video has helped SO MUCH! Than you very much. Great content!
Exactly my heart. I get it clearer that ketone production is to save us from using proteins for progressive gluconeogenesis; that it is vital to our system for purposes other than energy production, so that is why the body gets those F.A generating acetyl coA to be producing ketones too.
Thank you for making me understand all the principles all together ! :) very well and good explained because sometimes one can get lost in so many reactions and not get the point finally but this video makes it clear all in one! :D thank you :)
For anyone who has felt repulsed by the above comments, I’m sorry. There are many kind people in the world, but RUclips is often not the place to find them. I wish you all love and happiness.
It is interesting to know that in some plants and germinating seeds there does exist the glyoxylate cycle which allows for direct conversion of fatty acids to to sugars like glucose and sucrose. They managed to get around that issue of not being able to convert fatty acids to sugars, damn, nature is crafty.
Around the 8:20 mark, she says that "acetyl-coA is the product of fatty acid synthesis"...I'm assuming she meant to say that acetyl-coA is the product of fatty acid OXIDATION..right?
this lecture is so amazing that i had to subscribe before finishing it up. yhe voice alone made me fall in love with Biochemistry and this lecturer. let me look for your email now
great explanation! but I have a question. At time 14:55 , how are cells able to use/create this atp if it is not turned in to ketone bodies first? could you please explain this part? Thanks in advance!
I did a 7-day water fast last year, only drinking water with potassium/sodium salt. I learned everything within the 7 days including insulin/blood-sugar testing/oxalate/acetyl/ketone urine test.
~13:00 If the fasting/starving person is active would the ATP single stop the ETC Process? I am not sure of the math but what is the Calories to unit of Acetyl-coA? also it would be wonderful to have the Calories to Ketones conversion as well.
الاستيل co a عامل مترسب بعد عمليات الهضم المهم يساعد على هضم الدهون ال ketone bodies اللي ما تقدر بروحها (fatty acids نقصد ) تتحول لجلوكوز >> فتقوم بتحويلها pyruvate اللى بدوره ما ادري شيصيررفيه ينقلب فوق تحت ويتحول جلوكوز 😊 الحمد لله رب العالمين ترجمة عربية لمن يهمه الامر
During fasting or untreated diabetes, in the adipose cells, TAGs are broken down into FAs + Glycerol and the constituents enter the bloodstream and travel to the liver where FAs are taken into the mitochondria matrix where they undergo beta-ox. However, in the cytosol, doesn't glycerol enter GNG to form glucose?
In the keto diet, you are eating a lot more protein than usual, and restricting intake of carbs (sugar/glucose) to almost 0 so that your body uses nearly-only those dietary proteins for a fuel source. I think the idea is that it's harder to take in as many calories each day on a strict keto/protein diet compared to an uncontrolled/unrestricted diet, so you should have a net loss of Calories each day, leading to weight loss. And during the times between keto meals, your body is breaking down fat (FA oxidation) for fuel (also breaks down some dietary + stored protein), leading to less adipose tissue and therefore less fat, leading to weight loss.
Great video on starvation! I only have 1 question to ask....in the text I have read, during starvation, intermediates for the CAC are depleted due to feeding into gluconeogensis. Without intermediates like OAA, how is the acetyl CoA converted from ketone bodies fueling the CAC? I'm not understanding this step nor have I found anything that really answers it. Thats for the help
because gluconeogeensis is located only in the liver. But ketones, that are formed also only in the liver, travel into other tissues, like the brain and there they enter the CAC, and these other tissues have enough intermediates for the CAC, because gluconeogenesis is not located in extrahepatic tissues.
If you consume exogenous ketones (ex. mct oil, red raspberries, etc), in an otherwise normal (non-carb restrictive) diet, which fuel source will the brain use? Are there any genetic component or polymorphisms that would make the liver less capable of producing endogenous ketones from excess acetyl-coa? Is it widely accepted that diseases of the brain (alzheimer's, parkinson's, huntington's, etc) are likely the result of insulin resistance of the brain? And therefore ketone therapy may be helpful?
I'm just a novice on a low carb diet trying to get my head around all this. Am just wondering, once the body shifts into ketosis, why does it need to break down protein at all? Is there a reason it cannot just run on purely fatty acids & ketones alone? If the brain, etc, is able to use ketones as it's replacement glucose, while the rest of the body uses fatty acids. Then what does the body need that minimum level of glucose for?
+blk bbw In the beginning stages of fasting (before 3 days), the body breaks down protein to produce glucose (the body's main source of energy). Then after 3 days, the body starts saving protein as to maintain mechanical function of muscles. At the same time, the body goes into ketosis and produces ketones from fats as the new primary energy source for the body. The body cannot purely rely on fatty acids because it breaks down to acetyl CoA, and too much acetyl CoA creates a negative feedback that inhibits the Krebs Cycle so it can't make any energy, which is why it turns into ketones. Long-term ketosis can cause hypoglycemia and low grade acidosis. However, the benefits and repercussions of a long-term keto diet still has some debate.
So Acetyl Co-A could enter the Krebs Cycle as long as there is enough OAA, but in starving mode/diabetes OAA is needed to the gluconeogenesys so the excess Acetyl Co-A must go to the Ketons syntesys. Right?
I understood it that way, that in starvation mode body tries to reduce gluconeogenesis in the liver in order not to destroy our amino acids, instead, the liver produces ketone bodies, that are then transported into other tissues and there they undergo citrate cycle and in these other tissues there is enough of OAA in CC since gluconeogenesis is not located in extrahepatic tissues? But I am very unsure about this.
I was having trouble understanding how fat can be used to fuel cells requiring ATP very quickly, as the breakdown of fat requires oxygen to produce ATP. Once you said that the body STORES acetyl coa in periods of long term fasting it all made sense!! the fatty acids have already been broken down in the liver and are ready to go and be transported to cells in the way of ketones! AMAZING... i am now 7 days into full ketosis and feel stronger and more energetic in the gym which is what prompted my question..
+Walid Abdo Go away bot. Your BS lies are not needed here. Any medical professional knows that long term Ketogenic diet leads to arterial calcification, the acidity from the ketones in your blood draws calcium from your bones, combine that with increased saturated fat which leads to an increase in LDL and you have created the perfect situation for you to eventually have a myocardial infarction. There are no shortcuts in health.
I have been through severe starvation. About 5 and and a half weeks without food. If anyone is interested i have a detailed look at what this is like. Interestingly enough logic is not affected very much but very unfortunately emotions are very affected. Many of mt emotions were resorted to nothingness.
sorry, can anybody help me what are the diffenrences between normai acetyl coA (can do the Krebs cycle) and the 2C acetyl coA (cannot). i am confused, they are acety coA but one can and one cannot, sorry for my bad English.
I realize this was written a good while ago but: Acetyl CoA doesn't come in different forms, it's just Acetyl CoA, which has 2 carbons. However in order to enter Krebs cycle Acetyl CoA needs to react with OAA! And it can't do that if gluconeogenesis occurs, and we don't have enough amino acids that can participate as intermediates, because the cell will be depleated of its OAA because of: OAA -> PEP ->-> etc -> glucose! So Acetyl CoA + nothing can't enter the cycle.
But if I understand well, it's kid of impossible t avoid protein bread down as it occurs in the first couple of day of fasting? So If you fast for 2 days or 5 days you're still going to break protein, in the first two days that is. Is that a good idea if you're an athlete?
Beforehand, please correct me if my understanding is wrong! So, odd number of Fatty acyl chains can be converted to pyruvate(3C) to further synthesize glucose via gluconeogenesis. The main reason fatty acids canNOT be converted to pyruvate but only Acetyl-coA (or vice versa) is because fatty acids are usually even numbers and FA is synthecized/broken down in 2C units. Hope this made sense! :)
pryuvate is not a ketone, fructose is. ketone bodies are ketones like squares are rectangles. there are 3 ketone bodies: acetone, b-hydroxybutryate, and acetoacetate. although beta hydroxybutyrate is technically not a ketone but still is a ketone body. a ketone has a carbonyl group with 2 hydrocarbons side chains. also don't get confused with keto acids. pyruvate's conjugate acid, pyruvic acid is a keto acid
So.... If ketones have the body not eat up the protein, and fats cannot be converted to glucose... Why does one loose weight from prolonged starvation?
This is somewhat inaccurate video. Fat stores can be converted into glucose. It is 3 carbon end of fatty acid that can no longer be processed into glucose and is converted into ketone bodies (3 carbon, just like acetone). That is why individuals who are experiencing DKA have that acetone-like breath and can sustain on fat metabolism.
I see your thought process, but no, The body will use excess amino acids to fuel gluconeogenesis before breaking down muscle. So more fat will be broken down but the ability to synthesise new protei ns and build muscle is not as great until you ingest a high protein meal to replenish amino acid stores
So she is saying if we are fasting we are using protins as a source of energy despite we have saved all exstra energy as fat. I think she missed the point of starvation which is more like constantly eating lower calories then your body need insted of fasting which boosts you metabolism.
i don't understand why we needed the ketone body step. if we're backed up with acetyl-coA, why transform it into ketone bodies, only for them to be reverted to acetyl-coA again?
Because you have all these AcetylCoA's "all readied up but nowhere to go" because Krebs won't take 'em (actually Krebs can't take 'em because no electron carrier molecule is available since NADH can't unload - i.e. get oxidized - them to the ETC because excess ATP already has fedback to stop the chain.) So the AcetylCoA goes the ketogenesis route. Why? Because our dear brain can utilize them for power.
+Tony G. Reyes yes, a ketogenic diet can lead to acidosis, as all three ketone bodies are acidic and an abundance of them will overwhelm the blood's bicarbonate buffering system. This is essentially caused by the lack of diet glucose leading to a lack of insulin secretion, which promotes fatty acid release from adipose cells, which are turned into ketone bodies in the liver.
+paucceri Firstly, Acetyl Co-A can't cross the mitochondrial membrane, so unless convernted to ketone bodies it is stuck there. Secondly, in the fasting state many tissues use fatty acids for energy. Our brain can't use fatty acids for energy however, because they can't cross the blood brain barrier. However, ketone bodies (Acetoacetate and beta-hydroxybutyrate) can cross. Therefore ketone bodies provide our brain with an alternate supply of energy to glucose, which is in short supply and requires energy to make during fasting.
+paucceri I am going to breakdown your question into two parts: transport and metabolism. Transport: simply put, acetyl-CoA cannot travel through the bloodstream because it is insoluble. Ketones are water soluble and can travel through the bloodstream. Tissues and organs do need this acetyl-CoA for ATP, so ketones are sort of the packaged carrier system for acetyl-CoA to travel through the bloodstream. Metabolism: Too much acetyl-CoA inhibits its own use in the Krebs cycle. Producing ketones from acetyl-CoA reduces the amount of acetyl-CoA. With a lot more ketones (because of low ketone extraction by tissues from low insulin) and less acetyl-CoA, the Kreb Cycle is no longer inhibited. Ketones now have an easier time catabolizing into acetyl-CoA and producing ATP with the Krebs Cycle. +Kat Zibell Acetyl-CoA can cross the mitochondrial matrix as citrate through the citrate shuttle then reverting back to acetyl-CoA in the cytoplasm. However this is usually during fatty acid synthesis and the fed state. Agree with everything else you said though :)
Sorry but I dont understand... just say you starved yourself for 1 week but like you drink alot of water and you also just eat a little bit... when you finish starving yourself do you gain all the weight back after and also get s SLOWER metabolisim?? Please help
You will have so much energy after the first 2 to 3 days and u don't even think about food all u basically doing is cleaning out all that old stuff u had in your body for years you can go back to refeeding after or u can just do omad its especially good for people who need to loose a couple of pounds to lower their insulin levels due to diabetes
Great Video! Just have one question: are amino acids from protein breakdown the primary source for gluconeogensis during the initial phase of starvation (prior to the switch to using ketone bodies as fuel)? And what role does lactate from red blood cell glycolysis or glycerol from triacylglycerol breakdown play in gluconeogenesis during this phase? Anyone read up on this?
+FrostyPhoenyx thank you very much for your replay, i'm beginning to study nutrition and i really wanted know the metabolic pathway and the biochemical state in the body in persons who modify their eating behavior, changing from glucose to fats as their primary fuel source, the so famous "ketogenic diets" i'm dubious if they are really sustainable because i things they are toxic in the long run and people do not realize that.
+Tony G. Reyes no prob, good luck with your studies! yeah, I'm always kind of skeptical of these kinds of fad diets haha. I think if you want to look it up further you can look up ketosis.
From what I learned. Ketosis is benign and normal. Ketoacidosis (acidic blood pH) occurs when there are abnormal quantities of ketone bodies and is usually caused in diabetics by low insulin causing hyperglycemia (high blood sugar) and increased fat metabolism. As for sustainability, the keto diet (in nondiabetics) doesn't have long-term severe side effects except in children but you may have hypoglycemic (low blood sugar) conditions as well as low-grade acidosis. correct me if im wrong please
Im currently starving myself and enjoying this
Its time to stop
You can't do that you may seem like you're doing something right but you're not
@@kimseokjin9412 I'm dead now.
same rn
same
This was really fantastic. I felt you read my mind when you explained why acetyl CoA is not gluconeogenic even though it "seems" like it enters the TCA cycle and makes an entire round (just like how intermediates derived from gluconeogenic amino acids can actually be gluconeogenic via oxaloacetate). So the reason acetyl CoA (and therefore fatty acids, leucine, and lysine) is not gluconeogenic is that we lose the carbons as CO2. Further, PDH is irreversible. That was awesome. A good teacher preempts her students' confusions!
I uh huh gy u yu8
Sx
0
thank you for this wonderful summary
Excellent job very good brief explanation about a complicated process. Khan academy so awesome
amazing, I did wonder why Acetyl Co A cannot change back to Glucose
Hmm, I don't think the video explains this very well. You require OAA and Acetyl-CoA to form citrate in the cycle, so if there is no net gain of OAA, then gluconeogenesis cannot occur with FFA alone.
I was almost about to get confused before I could find such an amazing video.....You have cleared all the misconception regarding the integration of all this cellular respiration series.
This video is simply amazing. Very much appreciated!
I have been watching a few videos on the metabolism because of my pre-disposition to diabetes. I have started a Ketogenic eating lifestyle and this really starts to bring home my understanding of the ketogenic lifestyle. BTW, I've never felt healthier since I lowered my carb intake. My energy level is awesome, I immediately lost 20 lbs and the fat around my waist. Thanks for the awesome info.
Exellent explanation thank you - I struggled to understand this bit for the last 5 years and your 15min video was brilliant
Such a clear explanation of the complex process! Thanks.
Jasmine's voice is so therapeutic, I would not be studying but still watching this video
This is such a good video my goodness. This information is a must for those learning biochem and want to know the overall purpose of these starvation processes.
I have been struggling with the whole process of ketone production and use in Kreb's cycle but this video has helped SO MUCH! Than you very much. Great content!
Exactly my heart. I get it clearer that ketone production is to save us from using proteins for progressive gluconeogenesis; that it is vital to our system for purposes other than energy production, so that is why the body gets those F.A generating acetyl coA to be producing ketones too.
I need to know what happens to NAD+ and NADH during dka. Can't find any answers...
so many questions answered. thanks
A very clear explanation, thank you very much!
I love this video. Seriously so concise and easy to follow. Thank you!! MCAT in 9 days ahhh...
Great video. Very clear and concise.
These videos are amazing. Thanks so much
Thank you for making me understand all the principles all together ! :) very well and good explained because sometimes one can get lost in so many reactions and not get the point finally but this video makes it clear all in one! :D thank you :)
insanely helpful and clear!
This was so helpful! Thank-you!
This is the greatest explanations for this topic. It's very easy to understand.
Excellent explanation, thank you!
It turns out....that I learn more from this woman than my own teacher.
In my opinion you learn more from someone who is interested and knows what there teaching then some teacher that is just for grades.
That voice has not yet been burned by hardship.
That throat has not yet been burned by harddick.
+Frank Stein lmfao
Her voice is sexy still 😂😂
For anyone who has felt repulsed by the above comments, I’m sorry. There are many kind people in the world, but RUclips is often not the place to find them.
I wish you all love and happiness.
Really great series of lectures. Thanks again
Oh my god. I have to take notes on your notes!
Thanks for the video
very useful video. thank you!
Nice and elucidating
Superb !
Great explanation Jasmine, thanks :))
you are awesome thank you !
It is interesting to know that in some plants and germinating seeds there does exist the glyoxylate cycle which allows for direct conversion of fatty acids to to sugars like glucose and sucrose. They managed to get around that issue of not being able to convert fatty acids to sugars, damn, nature is crafty.
awesome thank you
Jasmine seems highly intelligent!
Bravo!
great teaching!
Around the 8:20 mark, she says that "acetyl-coA is the product of fatty acid synthesis"...I'm assuming she meant to say that acetyl-coA is the product of fatty acid OXIDATION..right?
+Junho Kwon yes
Jun Kwon free education 🍻
@@boombeatz27 Scientifically speaking, what's the difference?
A day of starvation?!? Nah! Nobody starves from a day of not eating! That could easily be a day of fasting.
Listen
e_z_squeezy listen to the words being said
Throw a few adderall and Ill go days without eating. Here we go ketones!!
this lecture is so amazing that i had to subscribe before finishing it up. yhe voice alone made me fall in love with Biochemistry and this lecturer.
let me look for your email now
well done
Love you! Thanks.
great explanation! but I have a question. At time 14:55 , how are cells able to use/create this atp if it is not turned in to ketone bodies first? could you please explain this part? Thanks in advance!
My ADD made its self known 3 minutes into this video.
the part about TG's not being able to be converted into glucose is technically incorrect because Glycerol is indeed used in the GNG process
I did a 7-day water fast last year, only drinking water with potassium/sodium salt. I learned everything within the 7 days including insulin/blood-sugar testing/oxalate/acetyl/ketone urine test.
😂 I hope you are not as white as your profile picture now? But how brave you are🤝👏
the narrator voice is lovely
Very cool video, thank you! This helps me out greatly. I promise you I will do my best not to forget about those 2 lost carbons! haha
This is a great explanation of a ketogenic diet. thanks.
in molecular level how depletion of amino acids are sensed?
~13:00
If the fasting/starving person is active would the ATP single stop the ETC Process?
I am not sure of the math but what is the Calories to unit of Acetyl-coA? also it would be wonderful to have the Calories to Ketones conversion as well.
what do u use for drawing like what program
best
الاستيل co a عامل مترسب بعد عمليات الهضم المهم يساعد على هضم الدهون ال ketone bodies اللي ما تقدر بروحها (fatty acids نقصد ) تتحول لجلوكوز >> فتقوم بتحويلها pyruvate اللى بدوره ما ادري شيصيررفيه ينقلب فوق تحت ويتحول جلوكوز 😊 الحمد لله رب العالمين
ترجمة عربية لمن يهمه الامر
During fasting or untreated diabetes, in the adipose cells, TAGs are broken down into FAs + Glycerol and the constituents enter the bloodstream and travel to the liver where FAs are taken into the mitochondria matrix where they undergo beta-ox. However, in the cytosol, doesn't glycerol enter GNG to form glucose?
I have a doubt, what are the 2 carbons entering with Acetyl CoA
@khanacademymedicine so is fat adaption a myth? Does this mean going keto actually causes breakdown of aminoacids into glycogen?
In the keto diet, you are eating a lot more protein than usual, and restricting intake of carbs (sugar/glucose) to almost 0 so that your body uses nearly-only those dietary proteins for a fuel source. I think the idea is that it's harder to take in as many calories each day on a strict keto/protein diet compared to an uncontrolled/unrestricted diet, so you should have a net loss of Calories each day, leading to weight loss.
And during the times between keto meals, your body is breaking down fat (FA oxidation) for fuel (also breaks down some dietary + stored protein), leading to less adipose tissue and therefore less fat, leading to weight loss.
so wait, the fatty acids are just supporting neoglucogenesis by converting the acetil-coa to energy necessary to produce oxalcetate?
your voice is so sweet
Great video on starvation! I only have 1 question to ask....in the text I have read, during starvation, intermediates for the CAC are depleted due to feeding into gluconeogensis. Without intermediates like OAA, how is the acetyl CoA converted from ketone bodies fueling the CAC? I'm not understanding this step nor have I found anything that really answers it. Thats for the help
You would still be breaking down some muscle protein to feed into the cycle.
because gluconeogeensis is located only in the liver. But ketones, that are formed also only in the liver, travel into other tissues, like the brain and there they enter the CAC, and these other tissues have enough intermediates for the CAC, because gluconeogenesis is not located in extrahepatic tissues.
@@antasimo You for one, ma or sir, are brilliant. God bless you.
Does this apply to prolonged severe calorie restriction ?
I haven't eaten anything but a package of ramen a month ago, I started out at 90 pounds, and haven't changed a bit.
I want to be rich.
If you consume exogenous ketones (ex. mct oil, red raspberries, etc), in an otherwise normal (non-carb restrictive) diet, which fuel source will the brain use?
Are there any genetic component or polymorphisms that would make the liver less capable of producing endogenous ketones from excess acetyl-coa?
Is it widely accepted that diseases of the brain (alzheimer's, parkinson's, huntington's, etc) are likely the result of insulin resistance of the brain? And therefore ketone therapy may be helpful?
@khanacademymedicine: @2:14 So, if this fatty acid (17C) is an odd number of carbons, can it still be able to contribute to the gluconeogenesis?
The last compound will be a Propionyl Coa (3C) which will be converted later on to succinyl-Coa for gluconeogenesis !
I'm just a novice on a low carb diet trying to get my head around all this. Am just wondering, once the body shifts into ketosis, why does it need to break down protein at all? Is there a reason it cannot just run on purely fatty acids & ketones alone?
If the brain, etc, is able to use ketones as it's replacement glucose, while the rest of the body uses fatty acids. Then what does the body need that minimum level of glucose for?
***** because red blood cell needs glucose for energy (and they can only use glucose for his energy)
+blk bbw In the beginning stages of fasting (before 3 days), the body breaks down protein to produce glucose (the body's main source of energy). Then after 3 days, the body starts saving protein as to maintain mechanical function of muscles. At the same time, the body goes into ketosis and produces ketones from fats as the new primary energy source for the body. The body cannot purely rely on fatty acids because it breaks down to acetyl CoA, and too much acetyl CoA creates a negative feedback that inhibits the Krebs Cycle so it can't make any energy, which is why it turns into ketones. Long-term ketosis can cause hypoglycemia and low grade acidosis. However, the benefits and repercussions of a long-term keto diet still has some debate.
The video forgot about glycerol (you break down triglycerides into FFA and Glycerol and the glycerol can be used in gluconeogenesis
So Acetyl Co-A could enter the Krebs Cycle as long as there is enough OAA, but in starving mode/diabetes OAA is needed to the gluconeogenesys so the excess Acetyl Co-A must go to the Ketons syntesys. Right?
I understood it that way, that in starvation mode body tries to reduce gluconeogenesis in the liver in order not to destroy our amino acids, instead, the liver produces ketone bodies, that are then transported into other tissues and there they undergo citrate cycle and in these other tissues there is enough of OAA in CC since gluconeogenesis is not located in extrahepatic tissues? But I am very unsure about this.
I was having trouble understanding how fat can be used to fuel cells requiring ATP very quickly, as the breakdown of fat requires oxygen to produce ATP. Once you said that the body STORES acetyl coa in periods of long term fasting it all made sense!! the fatty acids have already been broken down in the liver and are ready to go and be transported to cells in the way of ketones! AMAZING... i am now 7 days into full ketosis and feel stronger and more energetic in the gym which is what prompted my question..
+Walid Abdo Go away bot. Your BS lies are not needed here. Any medical professional knows that long term Ketogenic diet leads to arterial calcification, the acidity from the ketones in your blood draws calcium from your bones, combine that with increased saturated fat which leads to an increase in LDL and you have created the perfect situation for you to eventually have a myocardial infarction. There are no shortcuts in health.
Wonderful,
Now i know, what they mean, about being fat adapted
7:09 answers why acetyl-coa/fatty acids can't be used for gluconeogenesis
Do you have any references?
I have been through severe starvation. About 5 and and a half weeks without food. If anyone is interested i have a detailed look at what this is like. Interestingly enough logic is not affected very much but very unfortunately emotions are very affected. Many of mt emotions were resorted to nothingness.
Its very hard to explain what nothingness feels like
Wait...are you telling my body catabolizes the amino acids in my muscle before my fats? I'm no bio major :(
sorry, can anybody help me what are the diffenrences between normai acetyl coA (can do the Krebs cycle) and the 2C acetyl coA (cannot). i am confused, they are acety coA but one can and one cannot, sorry for my bad English.
I realize this was written a good while ago but:
Acetyl CoA doesn't come in different forms, it's just Acetyl CoA, which has 2 carbons.
However in order to enter Krebs cycle Acetyl CoA needs to react with OAA! And it can't do that if gluconeogenesis occurs, and we don't have enough amino acids that can participate as intermediates, because the cell will be depleated of its OAA because of: OAA -> PEP ->-> etc -> glucose! So Acetyl CoA + nothing can't enter the cycle.
would you say starvation increases the citric acid cycle activity?
But if I understand well, it's kid of impossible t avoid protein bread down as it occurs in the first couple of day of fasting? So If you fast for 2 days or 5 days you're still going to break protein, in the first two days that is. Is that a good idea if you're an athlete?
You're assuming it's breaking down good protein, when it is more likely to go after old broken proteins. Look up Autophagy.
I read somewhere that fatty acids can be used for gluconeogenesis..
Beforehand, please correct me if my understanding is wrong!
So, odd number of Fatty acyl chains can be converted to pyruvate(3C) to further synthesize glucose via gluconeogenesis.
The main reason fatty acids canNOT be converted to pyruvate but only Acetyl-coA (or vice versa) is because fatty acids are usually even numbers and FA is synthecized/broken down in 2C units. Hope this made sense! :)
Julia Yun Kyung Yi If in the end of the acyl fat chain degradation you got a 3 carbon product (a propyonyl-CoA), this can be used for gluconeogenesis
Ketones and ketone bodies are two different things people are mistaken . Some ketones aren't ketone bodies : pyruvate , fructose
pryuvate is not a ketone, fructose is. ketone bodies are ketones like squares are rectangles. there are 3 ketone bodies: acetone, b-hydroxybutryate, and acetoacetate. although beta hydroxybutyrate is technically not a ketone but still is a ketone body. a ketone has a carbonyl group with 2 hydrocarbons side chains. also don't get confused with keto acids. pyruvate's conjugate acid, pyruvic acid is a keto acid
What is the biological significance of the phenomenon, why acetyl -CoA from fatty acid can not be converted into glucose?
What's a crip cycle?
I need to know what happens to NAD+ and NADH during dka. Can't find any answers.
Lawd hep meigh!
But ketone crosses BBB through a transporter molecule(MCT1 & MCT2) not by diffusion.
So.... If ketones have the body not eat up the protein, and fats cannot be converted to glucose... Why does one loose weight from prolonged starvation?
This is somewhat inaccurate video. Fat stores can be converted into glucose. It is 3 carbon end of fatty acid that can no longer be processed into glucose and is converted into ketone bodies (3 carbon, just like acetone). That is why individuals who are experiencing DKA have that acetone-like breath and can sustain on fat metabolism.
How long
We have so few control of ourselves, animals
So doing cardio in the morning on a fasted state is bad? I lose more muscle than fat? please reply
I see your thought process, but no, The body will use excess amino acids to fuel gluconeogenesis before breaking down muscle. So more fat will be broken down but the ability to synthesise new protei ns and build muscle is not as great until you ingest a high protein meal to replenish amino acid stores
So she is saying if we are fasting we are using protins as a source of energy despite we have saved all exstra energy as fat. I think she missed the point of starvation which is more like constantly eating lower calories then your body need insted of fasting which boosts you metabolism.
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i don't understand why we needed the ketone body step. if we're backed up with acetyl-coA, why transform it into ketone bodies, only for them to be reverted to acetyl-coA again?
Because you have all these AcetylCoA's "all readied up but nowhere to go" because Krebs won't take 'em (actually Krebs can't take 'em because no electron carrier molecule is available since NADH can't unload - i.e. get oxidized - them to the ETC because excess ATP already has fedback to stop the chain.) So the AcetylCoA goes the ketogenesis route. Why? Because our dear brain can utilize them for power.
+Rudy Schneer a ketogenic diet can be toxic with the production of to much ketone bodies? Are they acid enough to chance the PH levels ?
+Tony G. Reyes yes, a ketogenic diet can lead to acidosis, as all three ketone bodies are acidic and an abundance of them will overwhelm the blood's bicarbonate buffering system. This is essentially caused by the lack of diet glucose leading to a lack of insulin secretion, which promotes fatty acid release from adipose cells, which are turned into ketone bodies in the liver.
+paucceri Firstly, Acetyl Co-A can't cross the mitochondrial membrane, so unless convernted to ketone bodies it is stuck there.
Secondly, in the fasting state many tissues use fatty acids for energy. Our brain can't use fatty acids for energy however, because they can't cross the blood brain barrier. However, ketone bodies (Acetoacetate and beta-hydroxybutyrate) can cross. Therefore ketone bodies provide our brain with an alternate supply of energy to glucose, which is in short supply and requires energy to make during fasting.
+paucceri I am going to breakdown your question into two parts: transport and metabolism.
Transport: simply put, acetyl-CoA cannot travel through the bloodstream because it is insoluble. Ketones are water soluble and can travel through the bloodstream. Tissues and organs do need this acetyl-CoA for ATP, so ketones are sort of the packaged carrier system for acetyl-CoA to travel through the bloodstream.
Metabolism: Too much acetyl-CoA inhibits its own use in the Krebs cycle. Producing ketones from acetyl-CoA reduces the amount of acetyl-CoA. With a lot more ketones (because of low ketone extraction by tissues from low insulin) and less acetyl-CoA, the Kreb Cycle is no longer inhibited. Ketones now have an easier time catabolizing into acetyl-CoA and producing ATP with the Krebs Cycle.
+Kat Zibell Acetyl-CoA can cross the mitochondrial matrix as citrate through the citrate shuttle then reverting back to acetyl-CoA in the cytoplasm. However this is usually during fatty acid synthesis and the fed state. Agree with everything else you said though :)
You forgot about Glycerol!
try moving the mic away from your mount and use a pop filter
Shouldn’t the molecule be more fat-soluble and not “water soluble” to be able to cross the blood brain barrier easier? 10:32
Isn’t glycerol converted to DHAP which facilitates gluconeogenesis? Isn’t glycerol a fat?!
10:32 sorry, but I thought water-solublity was NOT helpful for materials to cross the Blood-brain barrier.
After starvation, does your body gain back the fats?
After talking about saving our proteins, she means ketone bodies right...not ketones?
ketone bodies are ketones
Sorry but I dont understand... just say you starved yourself for 1 week but like you drink alot of water and you also just eat a little bit... when you finish starving yourself do you gain all the weight back after and also get s SLOWER metabolisim?? Please help
Julia young U can gain the weight back if u go back to the same eating habits
You will have so much energy after the first 2 to 3 days and u don't even think about food all u basically doing is cleaning out all that old stuff u had in your body for years you can go back to refeeding after or u can just do omad its especially good for people who need to loose a couple of pounds to lower their insulin levels due to diabetes
Smoke is coming out of my head.
Great Video! Just have one question: are amino acids from protein breakdown the primary source for gluconeogensis during the initial phase of starvation (prior to the switch to using ketone bodies as fuel)? And what role does lactate from red blood cell glycolysis or glycerol from triacylglycerol breakdown play in gluconeogenesis during this phase?
Anyone read up on this?
😜💨💨💨 mindblown
A question, does ketones bodies are toxic? Like in a "ketogenic diet" , is that type of diet is sustainable trough life?
+Tony G. Reyes in my class we learned that having too many ketone bodies in the blood is acidic and lowers blood pH which could be dangerous
+FrostyPhoenyx thank you very much for your replay, i'm beginning to study nutrition and i really wanted know the metabolic pathway and the biochemical state in the body in persons who modify their eating behavior, changing from glucose to fats as their primary fuel source, the so famous "ketogenic diets" i'm dubious if they are really sustainable because i things they are toxic in the long run and people do not realize that.
+Tony G. Reyes no prob, good luck with your studies! yeah, I'm always kind of skeptical of these kinds of fad diets haha. I think if you want to look it up further you can look up ketosis.
From what I learned. Ketosis is benign and normal. Ketoacidosis (acidic blood pH) occurs when there are abnormal quantities of ketone bodies and is usually caused in diabetics by low insulin causing hyperglycemia (high blood sugar) and increased fat metabolism.
As for sustainability, the keto diet (in nondiabetics) doesn't have long-term severe side effects except in children but you may have hypoglycemic (low blood sugar) conditions as well as low-grade acidosis. correct me if im wrong please
ah after looking it up I think you're right, its ketoacidosis that is dangerous and ketosis happens naturally.
i just wished u never stopped talking..... so sweeeeeeeeet