Re: Feed before a ride

Susan Evans Garlinghouse (
Sun, 23 Nov 1997 20:48:18 -0800

> Your reply is well-taken, Susan, but your prescription leaves the horse to
> begin competition at or near fasted glucose levels.

I would agree with this if the horse had no food at all during the
night, but if he has a moderate meal of grains the night before (say,
eight to ten hours before the start), then glucose is entering the
system from the small intestine for a fair portion of the night. If hay
is provided free-choice the day before and all night, then this is also
supplying a steady supply of glucose and VFAs from the hindgut. And
finally, if (as I personally prefer) soaked beet pulp is also provided
throughout the night, supplying yet another steady and moderate source
of energy, then I would think the blood glucose levels should be
considerably above fasted levels. I will agree that blood glucose would
be lower than had the horse been fed a pre-race meal of grain, but still
sufficient to support the burning of fats AND without inhibiting fat
oxidation as a primary fuel source during the race.

However, I don't have available right here any citations that document
what expected glucose levels would be in a horse being fed hay vs. a
fasted horse. If anyone has those numbers available, maybe they could
post them to the list for this discussion.

> "fat burns on the flame of glycogen--without muscle glycogen and blood
> glucose, everything shuts down--no matter how much fat is available. If the
> horse has no glucose/glycogen, he must necessarily burn protein, not fat.

I agree. I think my concern is that if too high a insulin level is
triggered by a highly soluble carbohydrate meal at the wrong time, both
glucose/glycogen is going to be unavailable in sufficient quantities as
the need arises. In addition, fat oxidation is going to be hindered as
well, resulting in insufficient fuel supply during sustained exercise
regardless of source.

Since the body can store plenty of fat (mine in particular), but only a
limited amount of glycogen, and since that glucose/glycogen is vital to
burning the fat stores, it seems to me that it would make sense to
"protect" your blood glucose levels by avoiding excessive insulin
response that would sequester the glucose and make it, at least
temporarily, unavailable to the energetic pathways.

Susan Garlinghouse