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ketosis vs glycolysis

Answered on August 19, 2014
Created January 19, 2011 at 9:50 PM

I noticed recently that people were talking about ways to stay just one the edge of ketosis and what not. I guess my questions is, why would you want to stay in glycolysis instead of going into ketosis (and vise-versa)? What are the benefits of each? I was under the impression (after a Robb Wolf seminar) that ketosis is the ideal stat of being... Thoughs?

E0250b1e6dc5ec1539ffb745042b4d80

(3651)

on March 06, 2012
at 03:15 AM

Not exactly. Ketosis means excess ketones. People think keto Stix need to light up so they are "burning fat." no, it means you are peeing fat (ketones). Ketosis for our purposes is a mid state that takes a couple weeks when you do LC. After that, you want to be burning those ketones and not peeing them.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on January 20, 2011
at 06:09 AM

So I read something more or less like "fat burning in the flame of carbohydrate" in a much more recent textbook. Is it just wrong because amino acids (the glucogenic kind) can be used to make pyruvate? Or is it "misguided" rather than wrong because it implies we need to *eat* carbohydrate -- since there are other ways of getting glucose to put into glycolysis (like gluconeogenesis from the aforementioned glucogenic amino acids). Anyhow these pathways seem like they all go around in circles sometimes. (When you said you'd be happy to write in more detail you got yourself in trouble, ha ha.)

47a42b6be94caf700fce9509e38bb6a4

(9647)

on January 20, 2011
at 04:42 AM

Oh yeah, that's good, thanks. It just seemed strange when you said "oxaloacetate from glycolysis" because in most diagrams of glycolysis (I've been teaching myself all this stuff recently) the endpoint is pyruvate. And then from there you can go back and forth with lactic acid, but the "straight line" is to go from pyruvate to acetyl-CoA, which is then the "entrance" into the Krebs cycle. But of course it's a cycle, so there are different entrance points, and pyruvate can also turn into oxaloacetate (as in the diagram up top there on the wikipedia link) and enter that way.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on January 20, 2011
at 12:06 AM

Wait, pyruvate is the end product of glycolysis (it's a 3-Carbon thingamajig), which then becomes acetyl-CoA to go into the the Krebs cycle. No?

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6 Answers

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5
4e40d2b9e1a762949a25b958762aa10d

(762)

on January 19, 2011
at 10:00 PM

Being in ketosis doesn't mean glycolysis isn't going on. Ketosis just means you have some ketone bodies in your urine indicating an that fat oxidation > sugar metabolism. For fat oxidation to proceed you need a bit of glycolysis (Technically, the Krebs cycle cannot proceed unless the acetyl-CoA from fat oxidation joins with oxalacetate from glycolysis.) So I don't think it's a question of choosing one over the other.

Reference: http://en.wikipedia.org/wiki/Citric_acid_cycle

The Krebs (or citric acid) cycle begins when oxalacetate combines with acetyl-CoA to form citrate. Oxalacetate is regenerated with each turn of the citric acid cycle but originally comes from glycolysis because it's precursor, pyruvate, only occurs in glycolysis. This gave rise to the misguided statement in the 80's that "fat burns in the flame of carbohydrate".

Does that answer your question, WCC Paul? If not, I would be happy to write in more detail

47a42b6be94caf700fce9509e38bb6a4

(9647)

on January 20, 2011
at 04:42 AM

Oh yeah, that's good, thanks. It just seemed strange when you said "oxaloacetate from glycolysis" because in most diagrams of glycolysis (I've been teaching myself all this stuff recently) the endpoint is pyruvate. And then from there you can go back and forth with lactic acid, but the "straight line" is to go from pyruvate to acetyl-CoA, which is then the "entrance" into the Krebs cycle. But of course it's a cycle, so there are different entrance points, and pyruvate can also turn into oxaloacetate (as in the diagram up top there on the wikipedia link) and enter that way.

47a42b6be94caf700fce9509e38bb6a4

(9647)

on January 20, 2011
at 06:09 AM

So I read something more or less like "fat burning in the flame of carbohydrate" in a much more recent textbook. Is it just wrong because amino acids (the glucogenic kind) can be used to make pyruvate? Or is it "misguided" rather than wrong because it implies we need to *eat* carbohydrate -- since there are other ways of getting glucose to put into glycolysis (like gluconeogenesis from the aforementioned glucogenic amino acids). Anyhow these pathways seem like they all go around in circles sometimes. (When you said you'd be happy to write in more detail you got yourself in trouble, ha ha.)

47a42b6be94caf700fce9509e38bb6a4

(9647)

on January 20, 2011
at 12:06 AM

Wait, pyruvate is the end product of glycolysis (it's a 3-Carbon thingamajig), which then becomes acetyl-CoA to go into the the Krebs cycle. No?

0
23fee01f18bd2b29387b826149ed91f0

on November 21, 2012
at 06:29 PM

I have had great success being Keto Adapted. You can see some of my accomplishments on my blog. :) http://blog.paleoforpower.com/2012/08/21/fat-vs-sugar-whats-the-better-energy-source.aspx

0
D20a993ad9ad695446a0573e545daa18

on March 06, 2012
at 01:56 AM

I seem to function SLIGHTLY better in ketosis than in glyco-whatever. I've stopped ketosis. I've noticed a small difference in my attention span and in memory, but nothing too significant. As long as I'm Paleo, I'm good. I've got ADHD. I'll be in permanent ketosis, once I turn 18, or go off to college. I've actually heard that MOST kids with ADHD are best in ketosis. I notice no SIGNIFICANT difference, so's long as I get plenty of omega 3's. I just need to eat plenty of meat. If I don't, I get water cravings. If I don't get enough omegas and too many carbs, my ADHD, dandruff, and skin problems are worse. They say to eat lots of rice if your an ADHD Paleo. Or at least, its the only safe starch. I've just added potatoes. EVERYBODY'S different, though. For me, its just omegas.

0
667f6c030b0245d71d8ef50c72b097dc

(15976)

on June 05, 2011
at 03:46 PM

Like others have said, the two are not mutually exclusive. Humans are NEver purely burning glucose or purely fat. Both are always going on, but most people today are of course running off of much more glucose for fuel than ketosis.

For the fit athletic people glycolysis' advantage is that it is much speedier, more efficient I suppose, way of fueling muscles when they are being called to do what is called glycolytic work: explosive fat twitch work.

I run on a lot of starch so I am pretty ready for action whereas my brother, who is an endurance cyclist and semi-runner, has been much more fat-adapted for ages. Hissports run fine under ketosis

0
0f65a70ecd48725612ec1e0bbb300f2d

on June 05, 2011
at 03:26 PM

In ketosis your body can run more efficiently. And most people feel better than they would onn a carb based diet.

E0250b1e6dc5ec1539ffb745042b4d80

(3651)

on March 06, 2012
at 03:15 AM

Not exactly. Ketosis means excess ketones. People think keto Stix need to light up so they are "burning fat." no, it means you are peeing fat (ketones). Ketosis for our purposes is a mid state that takes a couple weeks when you do LC. After that, you want to be burning those ketones and not peeing them.

0
F9a0b72f38860d7601afd5a45bb53394

(3618)

on February 17, 2011
at 11:32 PM

I guess you'd have to still be able to do glycolysis in ketosis because your body still has to get rid of extra sugar if it turns up. Even on Atkins Induction, you're getting some glucose-containing foods in your diet and that's got to go somewhere, otherwise it'd start causing damage.

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