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WHAT
IS THE GLYCEMIC INDEX?
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The
Glycemic index (GI) concept was first developed in 1981 by Dr
David Jenkins , a Professor of nutrition at the University of
Toronto Canada , to help determine which foods were best for
people with diabetes. Today the GI concept is of benefit not
only to diabetics, but to a wide range of people including coronary
heart disease sufferers, the hypoglycaemic as well as athletes
and slimmers.
The GI of foods is simply a measurement of by how much and for
how long carbohydrate based foods effect blood sugar levels.
Carbohydrate foods that break down quickly during digestion
have the highest GI. The glucose or sugar in the bloodstream
increases rapidly. On the other hand , carbohydrates which break
down slowly , releasing glucose gradually into the bloodstream
, have a low GI. |
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HOW
IS THE GLYCEMIC INDEX MEASURED?
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The GI
of pure glucose is set at 100 and every other food is measured
on a scale from 0 to 100 according to its actual effect on blood
sugar levels . Low GI Foods are ranked from 1 to 55 , intermediate
56 - 70 and high 71 - 100.
In order to test the Glycemic Index of a food people have to
have their blood sugar levels tested at pre-determined intervals
after eating foods containing carbohydrates. The GI of over
600 foods has been determined worldwide and more foods are being
tested on a weekly basis , overseas as well as in South Africa.
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High fat
foods that have a low GI may appear in a falsely favourable
light. In order to be of benefit it is not sufficient for
a food to simply be low GI, it also needs to be low in fat.
This is because fat can inhibit carbohydrate absorption, making
high fat products appear in a falsly favourable light by appearing
to have a low GI.
As a general rule, low GI products should not contain more
than 10% fat. Any low GI product with an elevated fat content
should be regarded with suspicion.
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