From: Dave Blake <dblake@popper.ucsf.edu>
Newsgroups: rec.bicycles.tech
Subject: Re: Sports drink substitutes? It's a matter of taste, pal.  Powdered  
	Gatorade
Date: 17 Sep 2001 03:35:14 GMT

Trevor Jeffrey <tre4@aol.comsprouts> scribed:
>  In article <slrn9q6m84.qpg.dblake@popper.ucsf.edu>, Dave Blake
>  <dblake@popper.ucsf.edu> writes:
>
>>People interested in cheap energy drinks should grab raw
>>maltodextrin at beer brewing stores. Maltodextrin breaks down
>>rapidly into glucose in the small intestine, and thus makes for
>>rapid energy that will not lead to malabsorption.

>  Use of pure sugars upset fat metabolism, insulin increases on
>  the ingestion of pure sugars as opposed to carbohydrates.
>  This increases the likleyhood of the bonk.  I would generally
>  use such a drink with caution on a ride, keeping it dilute
>  and alternating with pure water.

Insulin spikes have never been observed in exercising athletes.
They are minimal in well trained athletes anyway. One of the
larger sources of variance in insulin resistance is amount of
exercise.

Your small intesting contains enzymes that rapidly break down
all carbohydrates into simple sugars. Complex carbohydrates,
like maltodextrin, are not really any different to your GI
physiology than pure glucose and galactose.

The way to slow down carbohydrate absorption is adding fat,
protein, or fiber, to delay gastric emptying. None of those are
particularly desirable during cycling because diverting too
much blood flow to the GI system will reduce maximal cardiac
output and severely limit exercise capacity.

Pro athletic trainers know all this and juice up their athletes
on the road with glucose and glucose polymers.


>  As for after exercise, malt drinks are good, especially real
>  beer, cask fermented with live yeast, full of B vitamins
>  essential for energy metabolism.  Filtered and pasturised
>  beer or even bottle conditioned beer are not much use in this
>  respect as the yeast is extracted, killed, or mostly dead.
>  Cask conditined beer from the pub is what is needed.

I am beginning to think this is a pure troll. Whereas the
dominant source of energy in beer is ethanol, a carbohydrate,
it metabolizes directly into a acetic acid which enters the
citric acid cycle just like the last step of fat metabolism.
Because few sugars are EVER present, the metabolic pathways
treat it just like fat.

Further, those important B vitamins are mostly pissed away, as
ethanol inhibits ADH secreting cells in the hypothalamus. So
you get dehydrated and eat a lot of fat. Just what the doctor
ordered. If you want a post ride beer, by all means go for it.

But don't try to justify it with these arguments. Beer in any
amount that can impact metabolic pathways is pure evil for the
training athlete. Note that a beer on top of dinner would not
impact metabolic pathways. But 3-4 beers on an empty stomach at
a beer hall in Munchen would. Just ask for a Hefeweizen.

--
Dave Blake
dblake@phy.ucsf.edu