GLYCEMIC
LOAD
UNDERSTANDING GLYCEMIC
LOAD
The Glycemic Load is the most practical way to
apply the Glycemic Index to dieting, and is easily calculated by multiplying a
food's Glycemic Index (as a percentage) by the number of net carbohydrates in a
given serving. Glycemic Load gives a relative indication of how much that
serving of food is likely to increase your blood-sugar levels.
GL = GI/100 x Net Carbs
(Net Carbs are equal to the Total Carbohydrates minus Dietary Fiber)
As a rule of thumb, most nutritional experts
consider Glycemic Loads below 10 to be "low," and Glycemic Loads
above 20 to be "high." Because Glycemic Load is related to the food's
effect on blood sugar, low Glycemic Load meals are often recommended for diabetic
control and weight loss.
LIMITATIONS TO GLYCEMIC
LOAD'S USE
To calculate Glycemic Load, you must first
determine the food's Glycemic Index (GI), which can only be done via human
testing. GI testing is relatively expensive and very time-consuming. Human test
subjects are required, and only a limited number of laboratories currently
perform these tests. Consequently, GI data is only available for a very small
percentage of the foods that we consume.
The most prolific GI testing laboratory is based
in Australia, so a large portion of the currently tested foods are of
Australian origin. This further limits the usability of the data, because some
of the tested foods do not have equivalent forms in the U.S. or other parts of
the world.
To make matters worse, food manufacturers are
creating new food products at a much faster rate than GI testing can be
performed. Each year, tens of thousands of new packaged-food items are added to
grocery shelves, but only a few hundred foods are tested for GI. Because of
this, it's doubtful that we'll ever reach a point in time where GI is known for
all foods.
In addition to these limitations, there is no
recognized method for accurately determining GI for recipes, other than to
submit the prepared recipe for the previously described human tests. The
consequence of this is that a chef or home cook has no practical way to
determine the Glycemic Index or Glycemic Load for any of his own creations.
Clearly, what is needed is a way to estimate Glycemic Load when
Glycemic Index is unknown.
