The glycemic response is a personal attribute.
The absolute magnitudes of the glycemic responses are important for individuals trying to control blood sugar and/or body weight, but using published GI lists as a guide to control the glycemic response is not fully informative. This is because in calculating the GI, individual glycemic responses to glucose are normalized to 100. GI values are, therefore, relative and are not necessarily a reliable guide to the person's actual individual AUC when consuming a food. Without knowledge of the person's characteristic blood glucose responses, reliance only on the GI may be misleading
Interesting to see this study just now. Others have been saying similar things before:
Barry Groves exaplains:
What matters as far as your body is concerned is not the GI of a carbohydrate, but the total amount. A hundred grams of carbohydrate is a hundred grams of carbohydrate whatever its GI is.
Emma also had a good post way back:
I’ve been griping about the GI diet for a long time now – partly because of Dr. Bernstein’s evidence, but mainly because it encourages the consumption of foods that do bad things to your body. A low fat, low animal protein diet encourages the consumption of plant foods, particularly energy-rich ones like beans and grains in order to replace missing calories. Plants grow very fast and they are always one step ahead of us in evolutionary terms, particularly when it comes to protecting their seeds. Beans and grains contain lectins, phytates, phytoestrogens, goiterogens, coumarins, oxalates, salicylates, protease inhibitors, and cyanogens, all designed to prevent them from being eaten. Each one of these substances contributes and causes different problems, from autoimmune diseases, to mineral deficiencies, to thyroid problems, to sex hormone imbalances, to uncontrolled bleeding.