T
he chemical nature of carbohy-
drates is not a reliable indicator of
their physiological effect.
In an effort to clarify the physiological
impact of carbohydrates, the glycemic
index (GI) concept was developed
and published in 1981 as "Glycemic
Index of Foods: a Physiological Basis for
Carbohydrate Exchange" in the American
Journal of Clinical Nutrition. The GI is a
means of classifying carbohydrate-con-
taining foods based on their potential to
increase blood glucose. The initial objec-
tive was to provide improved advice to
people with diabetes regarding their car-
bohydrate intake. During the last 20 years,
research has been undertaken to evaluate
the usefulness of GI. The glucose
response to foods inherently varies from
person to person and according to the con-
text in which the food is consumed.
Reproducible and consistent GI measure-
ments are possible when undertaken in
accordance with established methodolo-
gy. The debate continues as to the useful-
ness and consistency of GI.
Professor Jennie Brand-Miller and
colleagues at the University of Sydney,
Australia, have developed a center for
the measurement of GI, and tables have
been published ranking over 1,200 foods
by GI, including pure carbohydrates and
commercial products. Although use of
GI remains controversial, its acceptance
is increasing, especially in Europe and
Australia. In the United States, GI has
gained less acceptance. For example,
one of the criticisms of GI is that it
measures the impact of individual foods
and does not necessarily consider the
amount eaten or foods in the context of
an overall diet.
Glycemic Response
By Beth Hubrich, R.D.,
and Lyn O'Brien Nabors
Contributing Editors
