|
THE GLYCAEMIC INDEX AND SPORTS PERFORMANCE
The rate at which glucose enters the bloodstream affects the insulin response
as outlined above. The higher the blood-sugar increase, the greater the amount
of insulin produced. As glucose is the fuel most preferred by the body, its
availability greatly affects the exercising muscle.
When we are talking about eating for peak sports performance, the timing of
the meal is crucial:
Before an event |
Low GI foods which are digested and absorbed slowly
are able to provide a constant supply of glucose to the working muscle
right into the end of a workout when the glycogen stores are running low.
|
After an event |
High GI foods rapidly top-up the depleted blood-sugar
stimulating insulin production, the hormone responsible for storing glucose
in the muscle tissue. Any glucose eaten after an event when blood sugar
is low and stores are exhausted is therefore sent straight to the muscle
where it is used for protein synthesis and is NOT STORED AS FAT. |
A meal containing carbohydrates must be eaten at least two hours before an
event otherwise nausea and stomach cramps may be experienced. Unfortunately,
many athletes found that by the time the two hours had elapsed, all of the carbs
ingested had already been used up as fuel before the event had even begun. Knowing
the Glycaemic Index goes some way to resolving this problem. Carbohydrates,
when packaged in a particular way, can provide a slow release of fuel available
for much longer than two hours in order to sustain the body throughout the event.
As we now know, foods with a low GI factor are digested slowly and provide a
steady and gradual supply of fuel. Eating low GI foods prior to an event will
therefore improve endurance.
Again, after an event it is important to replenish the supplies of glucose
used up during intense training. It is also a good idea to take advantage of
this state of low blood-sugar to eat foods rich in glucose as, following intense
training, glucose will be stored directly in the muscle tissue as glycogen and
promote protein synthesis and hence muscle growth. High GI foods provide the
necessary rapid boost in glucose and hence can encourage muscle growth following
an event.
|
