Re: Carbo loading products

[Tivers@aol.com]

In a message dated 1/5/99 7:50:44 PM Pacific Standard Time,
suendavid@worldnet.att.net writes:

<< So, based on 4.15 Mcal/kg and 4.65 Mcal/kg from glycogen and proteins,
 respectively, (call it 4.4 Mcal/kg average), if you strove for and
 relied primarily on non-fat sources for energy as you proposed with the
 rocket fuel analogy, then a horse is going to require about 19.5 pounds
 of glucose and/or protein to fuel himself during that ride, and that's
 totally ignoring the additional energetic costs for basic maintenance of
 the body.  Personally, I have to work too hard to add body muscle and I
 darn well don't want it burned as fuel, so let's just look at body
 stores of glycogen.  Between liver and muscle stores of glycogen,
 there's less than 16 Mcals worth of glycogen in the equine body, and
 that's wringing out every last drop.  16 Mcals is only 41% of the energy
 required for that 100-mile ride, so are you seriously proposing that the
 rest of the energy can be provided as carbo supplementation during the
 ride?  

Great calculations--came out to almost exactly what I said the carb/fat
burning ratio would be. Most of the rest of the energy would be provided by
FFAs, of course. However, a periodic carb boost can do no harm and might
prevent fatigue and injury, as well as delivering better performance.


>Allowing for 90% efficiency, you'd have to feed roughly 14 pounds
 of carbocharge to supply the required energy.  Does that really seem
 reasonable or practical, rocket fuel or not?>

Not of CarboCharge. You'd need very little of it to see an improvement in
attitude and performance. 

>  And that's just for a
 back-of-the-pack completer with a lightweight rider.  How many pounds
 would you have to try to stuff down the throat of a heavyweight horse
 and rider trying for top ten?>

You're missing the point. I'm not, and never have, talked about attempting to
deliver ALL the working energy via carbs. That would be as dumb as attempting
to deliver ALL the working energy via FFAs. There is a significant part for
both--and hopefully thos bases are covered before much in the way of protein
is catabolized. 
 
 >OK, so let's look at NOT forcing the energetic pathways to rely on
 glycogen, let it just trundle along 65% fats and 35% glycogen like the
 horse is evolved to do.  A horse in good condition has enough body fat
 to ensure a virtually endless supply of fatty acids without running out,
 so that's not even an issue.  That leaves 35% of the energy requirement,
 or only 13.65 Mcals for the glycogen to supply.  Assuming the horse
 starts out with a full tank, and continues to eat normal feeds
 throughout the ride, then there's sufficient glycogen to supply what's
 needed without carbo-supplementing---not tons of it lying around, but
 for most horses, enough. > 

Well, you're making some broad assumptions there. Concerning initial
carbohydrate availability, digestive efficiency, appetite, etc. Without
sufficient blood glucose, FFAs will be preferentially used, disabling a good
proportion of the available carbohydrate. Fat is intended for low energy
work--and that is what you get--a low energy horse. The occasional dose of an
easily absorbed carbohydrate ensures the use of available carbohydrates. 


>I will absolutely agree that in some horses,
 maybe even a majority, performance might very well be enhanced by
 supplementing, just to ensure that there *is* enough, and that plasma
 glucose levels remain consistent>

Glucose levels are never consistent--they're all over the place. What you mean
is a sustained elevation of blood glucose as opposed to hypoglycemia.

 >and available---especially in horses
 running closer to their anaerobic threshold and therefore using up more
 glycogen and at a faster rate.>

Have you ever seen the muscle biopsy studies demonstrating that a horse can
work for hours, come back exhausted, and still have nearly 100% of the initial
glycogen content in FT muscle cells--it's a horse study, one of the early
ICEEPs, Sweden or San Diego. Bursts of speed, or aggressive hill climbs can be
very benefical in the endurance horse, mobilizing that glycolytic pathway and
providing a lactic acid cascade to the oxidative pathways for additional,
fast-acting fuel. 

>  It's a great theory/practice when used
 intelligently, really worth alot of further research (both field and
 clinical) and is really an exciting development in endurance horse
 nutrition.>

Well, I'll go along with that of course.

>  But, I think ignoring the horse's basic energetic physiology
 and forcing him to rely on glycogen as a primary fuel sounds pretty
 penny wise but pound foolish to me.  At least for distance horses.>

Pretty foolish to me, too. Who said that? What I said was that glycogen had to
always be available in significant quantities and that blood glucose should
remain significantly above fasting levels. This is easy to achieve with
periodic feedings of easily absorbed carbohydrate. 
 
 
 > 
 > By the way, on your recommendation I did get Lon Lewis' latest book. Still
a
 > pretty bright fellow and certainly not in love with fat. I'll pull some
quotes
 > for you when I get back.
 
 I'm surprised to hear you say that---his in-depth discussions of fat
 supplementation for equine athletes seems to pretty strongly support it
 for numerous reasons.  Quite clearly and succinctly.>

I'll endeavor to get some clear and succinct quotes for you when I return.
 
 > 
 > Meanwhile, you can only deny your own experiences for just so long before
you
 > realize that something's wrong with your calculations. What's wrong is the
 > underlying premise.
 
 >Well, as always, we may just have to agree to disagree---I agree that
 carbohydrate supplementation is helpful to some horses...but the
 operative word there is *supplement*.  The hard numbers just don't
 reasonably support your theory in practical application.>

You consider 2 ounces every 2 hours to NOT be a supplement? You're not even
attempting to understand what I'm saying. 

ti