Adding Substance to the Glycemic Index
The glycemic index is such a big nutritional deal for people with diabetes that it has sprouted spin-offs. One of the most well known of these is the glycemic load. But many people might find the “substance glycemic index” to be even more useful.
People are still arguing about how useful the glycemic index is. But there can’t be any argument that carbohydrates, far more than anything else, can make our blood glucose go up. Dr. David J.A. Jenkins at the University of Toronto published the first glycemic index study in 1981, and since that time hundreds of researchers around the world have added to our body of glycemic knowledge. You can find the tests of more than 750 foods at mendosa.com/gilists.htm.
The glycemic index simply ranks different foods according to how much they raise our blood glucose. The higher the food’s index the more troublesome it is for people with diabetes. The scale that the glycemic index uses is from 0 to 100. If something has no carbohydrates its glycemic index is 0. However, if a food increases blood glucose as fast as dietary glucose, it has an index of 100.
The point of all these glycemic studies is that the carbohydrates in different foods are not all alike. Nothing could be more wrong than “a carb is a carb is a carb,” as some people have said. It is true that “a rose is a rose is a rose,” as Gertrude Stein famously wrote, but a rose doesn’t have any carbohydrates!
The glycemic index compares how much a standard amount of carbohydrates will raise your blood glucose. It doesn’t tell you how much of that carbohydrate is in a serving of a particular food. You need to know both things to understand a food’s effect on blood glucose. That’s where the glycemic load comes in.
It relies on a “standard portion size.” But we don’t always eat a standard portion.
“I’m not a portion eater,” says Derek Paice, an engineer who has had type 2 diabetes for more than 15 years. To overcome this difficulty he reformatted the glycemic index so that it is based solely on the weight of food.
His website, dapaice.com, gives a list of more than 70 equal-weight foods ranked in the order of their effect on blood glucose. Look for the list in a PDF file under the Potpourri area, and you will find it and much more. He calls it the weight-based glycemic index the “substance glycemic index” and explains the calculation procedure. If your favorite food is missing but you know its glycemic index, you can convert it to the weight-based index.
Derek did many tests to validate the reformatting procedure. In an extension to the list of foods he includes some practical meal and snack ideas. His purpose is to help those with type 2 diabetes select food by applying the scientifically-obtained glycemic index. You don’t need to know anything about food nutrients. If you can estimate weight you can apply the SGI. This is the method he uses to control his blood glucose. His latest A1C was 5.3%.
In the PDF file, Derek includes other interesting issues relating to diabetes, including a way to personalize SGIs so that you can estimate your A1C.