How much GNG?

(Barbara Greenwood) #1

From a tweet by Shawn Baker:

The amount of glucose that one’s body needs is equal to the amount which it makes in the absence of carbohydrate!

Anyone know of anything to back this up? How much glucose do we make through GNG? What controls it?

(Michael Wallace Ellwood) #2

It just about has the ring of plausibility to my ears - which does not make it correct, of course. :slight_smile:

I think the only way of knowing would be with some sort of controlled lab trial, with people’s inputs measured, regular blood tests, and so on. Even then, it might not be easy.

But perhaps such tests have actually been done.

I don’t know if this helps:

https://themedicalbiochemistrypage.org/gluconeogenesis.php

There’s an awful lot of detail there (and I have barely skimmed it, to be honest).

(L. Amber O'Hearn) #3

There is a possible conflation here.

The body can make much more than we need. See for example this slide from Eric Westman:

But then there is the question of what is actually produced by a keto dieter, which is a different question. In this case I would agree with Shawn, just based on logic, but I would phrase it in the other direction:

“The amount of glucose that one’s body makes in the absence of carbohydrate is equal to the amount which it needs.” And I say that because it’s a demand driven process. It makes exactly what it needs, almost by definition.

#4

On the same topic Amy Berger linked to this post on ketogains which is an interesting read http://ketogains.com/2016/05/protein-over-consumption-ketosis/

Increased protein doesn’t equal increased gng-derived blood glucose that seems to be reasonably clear from the studies (in my mind at least) but it does increase insulin, decrease ketones and increase bg (only in some people?) so can often be seen to have done so.

In summary, too much protein may give impression that it led to increased gng but in fact it produced similar effects through a different mechanism…

(Barbara Greenwood) #5

Thanks for all replies, I may comb through the links in more detail when I have time later, but a quick question: do any of these studies differentiate between people with and without T2D?

The reason I ask is that, from my reading, I have gathered that the inability of insulin to damp down the release of glucagon is one of the enduring aspects of T2D. Glucagon switches on GNG, so in people with T2D, GNG happens even when both insulin and glucose are high.

(L. Amber O'Hearn) #6

Yes, I’ve tried to articulate that same argument dozens of times in informal internet conversations, but without much success. This post tries to point at that phenomenon: http://www.ketotic.org/2013/02/protein-ketogenesis-and-glucose.html, by pointing out that protein in keto dieters raises blood sugar, which probably increases glucose oxidation, which would then reduce ketogenesis.

(L. Amber O'Hearn) #7

This blog post of mine seems relevant to that: http://www.ketotic.org/2013/01/protein-gluconeogenesis-and-blood-sugar.html

In it I provide some evidence that the insulin to glucagon ratio determines ketogenesis through regulating blood sugar. If diabetics have impaired glucagon inhibition, that would explain both why they have a blood sugar increase in response to protein (like ketogenic dieters and unlike non-), and it would explain why diabetics even on keto have a more acute response to protein that makes it harder to maintain ketosis without protein restriction.