On Thu, 3 Jan 2002 13:33:57 -0500, Todd Moody <[log in to unmask]> wrote:

>According to Walsh (http://www.zonehome.com/met/met.htm), we use about
>180g of glucose per day, mostly by the brain and red blood cells.  That
>would vary somewhat by body weight, because of differences in blood
>volume, but not all that much.  Utilization of glucose by the brain
>should not vary much either.  So I take this to be a ceiling value:
>anything more than 180g/day is converted to SFA anyway.

Are the typical 180g/day a ceiling?
Or why insists the body to spare glucose only for the tissues for which it
is essential? Well, I think it makes sense for the body to do that as
possible, to spare the high octane fuel for the tissue who needs it. Ok.
But a ceiling?

It doesn't look probable for me that the average cell (like muscle) should
restrict itself to fat, if glucose would be readily available.
For a carb eating animal (ordinary primates) this would mean that
the production-of-fat-stage always had to take place first.
And fat production is done only in fat tissue and liver tissue, while
glycolysis and further energy production out of glucose can be done
in *any* cell.

Re-reading the Walsh papers ( http://www.zonehome.com/met/metlipid.htm point
3.) I noticed that a thiamin lack cannot be circumvented by fat production
as I suggested before. Because fat is made out of AcetylCoA. This is *after*
the pyruvate stage, and exactely the point, to which the fat energy is
delivered back when used.
Eating fat directly however can spare thiamin.

At the moment I look for annother explanation, why the intermediate energy
storage in fat is preferred over that in glycogen (some other vitamins and
Zinc come into the play).

> The other
>point, which Amadeus and I argued many times here, is whether SFA
>contributes to insulin resistance.  I admit that there is some evidence
>that it does (see
>http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_u
ids=8596494&dopt=Abstract,
>for example.  I think Sears has other references on this), although I
>still find the whole thing confusing and the evidence equivocal.

Interesting reference.
I note that the SFA part of *membranes* were tested, not the SFA intake.
SFA membranes are less permeable to nutrients and hormones (insulin).
You said that you assume the SFA in your diet will be used as fuel,
provided the amounts eaten are with in the usable range (some 1500 - 2000
kcal/day).

I think that the not-availability of short-chain EFAS (LA,LNA) is what
would force membranes to be made from SFA/MUFA.
This would make sense to show up as  dangerous,
as low-EFA food (below 20%) would be hard to find in wild food.
And wild food beeing natural for humans.

I find your posting and the one of Don Matesz regarding the Cordain book
both well taken and very necessary to say.

regards, Amadeus S.