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Ketosis halts gluconeogenesis?

Answered on August 19, 2014
Created January 16, 2012 at 12:27 PM

I've come across this in The Paleo Solution book, but now I'm debating this with a chemist who says it's just not true.

I've found a couple of references to this but only in conjunction with drinking alcohol and being in a fasting, ketogenic state. Anyone have anything on this? Any literature or studies confirming this? What byproducts of ketosis are halting the conversion of amino acids to carbs?

Thaks, guys! K.

B8592e62f9804ddabae73c1103d6bcb9

(1956)

on January 16, 2012
at 02:12 PM

Ketones are used instead of protein turning into glucose, ketosis is protein sparing. This is a good thing, it stops you losing as much muscle mass during fasting, starvation, or long term low/zero carbing.

65b327e053ca531a6916d43c19e1eaad

(143)

on January 16, 2012
at 01:29 PM

Sure, carbs are needed for life, I get that. I was mostly confused about the degree of the inhibition Wolf was talking about. Is the GNG rate in ketosis lower that it is when not on a low/no-carb diet? By logic it would be higher, since the glucose leveles in the blood are lower. Yeah, see me being confused :)

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 16, 2012
at 01:21 PM

I thought the fatty acids broken down to fuel GNG were the source of the ketone byproducts?

4145b36f1488224964edac6258b75aff

(7821)

on January 16, 2012
at 01:15 PM

GNG doesn't create ketones. It's the process by which the liver manufactures glucose: http://en.wikipedia.org/wiki/Gluconeogenesis

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5 Answers

8
4145b36f1488224964edac6258b75aff

(7821)

on January 16, 2012
at 01:12 PM

Humans have an absolute requirement for blood glucose. If you are eating zero carbs, you would go into a coma and die if you were incapable of producing blood glucose via gluconeogenesis.

A more accurate statement would be that ketosis greatly reduces gluconeogensis relative to the early stages of a transition from high carb to low or no carb. For the first few days/weeks, your body will try to make up the carb loss via GNG, but as you adapt to using ketones this will tail off.

It won't ever stop completely, because some tissue in the body can't ever make the switch.

Since this is basic physiology I think wiki works as a source:

http://en.wikipedia.org/wiki/Ketosis

65b327e053ca531a6916d43c19e1eaad

(143)

on January 16, 2012
at 01:29 PM

Sure, carbs are needed for life, I get that. I was mostly confused about the degree of the inhibition Wolf was talking about. Is the GNG rate in ketosis lower that it is when not on a low/no-carb diet? By logic it would be higher, since the glucose leveles in the blood are lower. Yeah, see me being confused :)

B8592e62f9804ddabae73c1103d6bcb9

(1956)

on January 16, 2012
at 02:12 PM

Ketones are used instead of protein turning into glucose, ketosis is protein sparing. This is a good thing, it stops you losing as much muscle mass during fasting, starvation, or long term low/zero carbing.

4
1c67bc28f4e44bbb8770b86df0463df3

on January 16, 2012
at 02:37 PM

In non diabetes Type I humans, human blood always has glucose in it. Even in deep ketosis, 0 carb for months states.

Even in deep ketosis the brain needs aprox 30 grams/day of glucose. The rest of the energy coming from Ketones.

Once adaption occurs much of that glucose comes from the liver creating it via the glycerol backbones of TFAs.

Prior to adaption much of that glucose comes from the conversion of amino acids (once the liver is empty of glycogen). In a non ketogenic state, the brain needs about 100 grams of glucose per day.

Only death halts gluconeogenesis.

1
Ccacf7567273244733bc991af4ac42ed

on January 16, 2012
at 01:13 PM

--On edit--

I've now found the part of the book you're referring to - as I recall, gluconeogenesis is the process that creates the initial ketone byproducts in the first place. Once begun, the breakdown of the triglycerides provides necessary glucose - as the amount needed is vastly reduced by ketosis. However I think this would only apply in full ketosis which can take weeks. I don't think gluconeogenesis gets switched off just like that - it would be a more gradual down-regulation in the absence of dietary protein. I'm not sure if that's what Robb was referring to though.

4145b36f1488224964edac6258b75aff

(7821)

on January 16, 2012
at 01:15 PM

GNG doesn't create ketones. It's the process by which the liver manufactures glucose: http://en.wikipedia.org/wiki/Gluconeogenesis

Ccacf7567273244733bc991af4ac42ed

(5198)

on January 16, 2012
at 01:21 PM

I thought the fatty acids broken down to fuel GNG were the source of the ketone byproducts?

0
7bf306ada57db47547e9da39a415edf6

(11214)

on October 19, 2012
at 09:26 PM

I've not heard of this. Gluconeogenesis can lower ketones. The system seems to be set up to be preferential to carbs, and if you have a lot of extra protein around, it tends to increase insulin levels. I think that messes with ketone levels as well, but I am not totally clear on that part.

The quote seems backwards, unless he is describing a particular situation.

0
7b4641bc7c610f2944da66f79cc3378a

on October 19, 2012
at 08:51 AM

According to Lyle McDonald, ketosis slows down gluconeogenesis as soon as tissues like skeletal muscles are adapted to use ketones instead of glucose. This happens at the final stage of starving (day 4 or later). Before that, gluconeogenesis is even higher as the liver breaks down proteins to compensate lack of glucose if no dietary carbohydrates are present. But GNG is never stopped completely as even in deep ketosis the brain needs about 25% of its fuel as glucose. Read more at “The Ketogenic Diet: A complete guide for the Dieter and Practitioner” by Lyle McDonald.

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