On Wed, 27 Oct 1999, Wade Reeser wrote:

> >When glucose-dependent cells are tapped out of
> >fuel, and glycogen stores to feed them are exhausted, the need
> >for sugar and not fat will be felt.
>
> First,  do you think you in fact have exhausted all glucose stores
> (glycogen)?  The
> cyclic ketogenic dieting  describes a glycogen depleting workout at the end
> of the
> week.  This workout is quite repetitious, severe and long in order to
> deplete all glycogen
> stores.

Good question.  I can't say with certainty that I have completely
exhausted all glycogen stores, but I can say that I have pushed
them low enough that the craving for sugar (in whatever form) is
clear, urgent, and unmistakable.  Experientially, I know the
difference between this sort of craving and the more "addictive"
sort of sugar craving that is not linked to intense exercise.
For one thing, the post-exercise craving promptly goes away after
I have some fruit, or dates.  The other kind of sugar craving
only gets worse if I yield to it.  Second, fat simply does not
help with the post-exercise craving.

> Second, trappers, artic explorers and Inuit have probably worked day to day
> more stenuously
> in both muscular exertion and endurance yet have never (?) complained of
> "sugar cravings"

I actually have no real idea as to how much glycogen-depleting
exercise they do, or what they crave or complain about.  It's
clear enough that one can be trained to high levels of endurance
performance on fat alone, though.

> Anyway, this may suggest that your personal cravings are not one of general
> nature and
> may have other etiologies.

It's possible.  I still conjecture that the ability of the liver
to perform gluconeogenesis may not be uniformly adequate in all
individuals, and this would explain a lot.  If, for whatever
reason, my liver cannot put out enough sugar to meet the demand
then cravings are just the beginning of the hypoglycemic symptoms
I can expect.  What we don't know is how typical my experience
is.  There is plenty of testimony that a continuously ketogenic
diet erodes the performance of weightlifters, and the reason is
that gluconeogenesis cannot keep up with the demand for sugar.
It wouldn't be surprising if this erosion of performance were
accompanied by cravings, though.  It also wouldn't be surprising
if a trained lifter can do a lot more than I can before reaching
the point of glucose exhaustion.

Todd Moody
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