On Fri, 12 May 2000, Julie Kangas wrote:

> > In addition, consider that it doesn't contain carbohydrate, which is
> > mandatory to fuel the brain.
>
> HUH?!?  Did I wake up in a parallel universe this
> morning?
>
> My readings of the Eades' two books make me recall that
> carbohydrates are _not_ required by the human body.
> I don't have my references nearby, so maybe someone
> else can chime in.  What is the prefered/mandatory fuel
> of the brain?

Glucose is the required fuel for certain tissues in the body,
including some brain cells, all red blood cells, fast-twitch
muscle fibers, and some cells in the retina.  There may be
others, but these are the ones that come to mind.  These cells
cannot use fat for energy.

But the glucose they need doesn't have to come from dietary
carbohydrate.  It can be produced from protein, and in fact 58%
of the protein that we eat is converted to glucose.  This process
is gluconeogenesis.  Thus, these tissues can get their glucose
even though one's dietary carbohydrate intake is zero.  Amadeus
is right, and the Eades are right too, in the sense that
*dietary* carbohydrates are not needed by the human body.

On the other hand, there is no good reason to depend exclusively
on gluconeogenesis for the glucose that one needs, and some
reason not to do so.  For one thing, gluconeogenesis is triggered
by the stress hormone cortisol, which is released when blood
glucose levels drop too low.  But cortisol has undesirable
effects as well, so it's not such a bad idea to use dietary
carbohydrate to keep blood glucose up.  Thus the Eades don't
recommend eating less than 40g of carb per day, as a bare
minimum.

Todd Moody
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