Jenny Ruhl casts doubt on the value of the Glycaemic Index for people with diabetes, and in general, in her article "Is the Glycemic Index a Scam?" Here is an extract:
"Foods that work well for a normal person, like whole grain oatmeal, may cause a blood sugar spike just as high as white bread in a person with diabetes. That whole wheat bread raises blood sugars the same amount as does white bread when fed to people with diabetes was recently documented in a published study:
Dietary Breads Myth or Reality. Banu Mesci et. al,
Diabetes Research and Clinical Practice Volume 81, Issue 1, July 2008, Pages 68-71
The only reason for a person with diabetes to learning the Glycemic index values for various foods is that if you are injecting insulin, knowing the GI value can help you time your insulin so that it peaks in the bloodstream at the same time that the glucose from the foods you ate reaches it.
Except that even this is more complex than it sounds, because there is yet another problem with applying the glycemic index. The GI values are established by testing each food in isolation. But we don't eat these foods in isolation, we eat them as part of a meal.
And when you
combine foods in a meal, their GI values change dramatically. Any high carbohydrate food eaten with fat will digest more slowly than it does when eaten alone. Eating a lot of food at once will also slow digestion.
So while white bread might have a very high GI and be completely digested by two hours, A slice of pizza that contains the same amount of carbohydrate as three slices of white bread may not digest completely until 4 or 5 hours have passed, thanks to the very high fat content of the cheese and the sheer bulk of the food.
In fact, the table of GI values cited above gives a higher fat Pizza the GI value of 30--which is one of the lower values to be found on that table, though you never will hear nutritionists telling people to eat a diet rich in healthy high fat pizza--and you won't hear it from me either. The combination of all that carbohydrate and fat is probably the most unhealthy one you could come up with and though it takes it a while to digest when pizza does digest it can give people with diabetes some of the highest blood sugars they are ever likely to see.
All this should make us rethink just how "healthy" all those low GI foods really are. If we really want to eat foods that won't raise our blood sugar or stimulate insulin response, we will be a lot better off eating protein, fat, fresh greens, and colorful fresh low carbohydrate vegetables in place of any carbohydrate-rich foods.
And when we do eat foods with carbohydrate in them, no matter what their GI might be, we should consider the total amount of carbohydrate in that food, not just the speed with which it digests.
Why Do We Hear So Much About Low Glycemic Foods?
It is not coincidental that over the past five years the once obscure GI theory, which was first published in 1981 and
completely ignored for the next 20 year has suddenly risen to prominence.
A major reason is that the food industry reacted to the "low carb diet craze" that swept the U.S. around the year 2000 by funding a well funded and well orchestrated media campaign to promote this hitherto obscure and neglected theory. And they did a masterful job of it."
You can read the whole article here:
http://www.phlaunt.com/diabetes/22168291.php