On Mon, 14 Jun 1999, Amadeus Schmidt wrote:

> I don't know where you get the 58% from, but it looks similar to
> the protein quality measures.

I first saw it on the lowcarb list and later was able to confirm
it in a physiology textbook.

> If meat has a protein quality of 67% (maybe a little less because
> the 100% was the best found in one experiment, ideal maybe better)
> then 33% of the amino acids aren't used for (own protein) anabolism
> and have to be "digested" to glucose anyway.
> After that RDA computes with a safety factor of about 2, and
> after that most people already have well over 100% RDA protein,
> there is a big percentage of protein used as fuel anyway.

I gather that the 58% is not dependent on the amount or type of
protein ingested, but I am not certain about that.

> >  Second, and more important, protein is the
> >only significant dietary factor causing the pancreas to secrete
> >glucagon, an important hormone that balances insulin. ....
>
> Eating protein as fuel (giving glucose) still needs insulin to permit
> *usage* of that glucose as fuel or for anabolisms.

No question about that, at least as far as anabolism is
concerned.  I'm not sure that insulin is needed for usage of
glucose as fuel, but in any case, according to the Eades protein
causes an insulin response that is about 40% that of a comparable
amount of carbs.

> Usage of fat as fuel is therefore somehow different from protein
> and carbohydrate which are similarily functioning through glucose.

Yes, usage of fat as fuel involves a different metabolic pathway
altogether.

> During each night we all (? :-) ) have the overnight fast
> where our body has to live on its storage (glycogen and fat).
> This requires glucagon, we all use it everyday heavily.

Yes, but carb consumption tends to suppress glucagon, during the
day.

> Do we need protein to promote "more" glucagon?

Yes, I think so.  This, I think, is the point that Barry Sears
has helped to make clear.  Insulin and glucagon have distinct
effects on the eicosanoids, which have far-reaching health
effects.  His protein recommendations (high, by your standards)
are calculated to provide a balance between glucagon and insulin
throughout the day, not just at night.

Having said that, I acknowledge that just cutting calories
sufficiently also has the effect of increasing glucagon
secretion, since glucagon is needed to liberate stored fat and
convert it to free fatty acids that can be used as fuel.

Todd Moody
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