Glycemic Index Explained
There have been diet fads after diet fads, but I think this Glycemic Index (GI) is one of the best diet ideas that’s come around since the 1970’s. As you may know, the Glycemic Index is a way to test the amount your blood sugar goes up after eating a certain amount of a certain food. For instance, in most of the older studies the researchers used a slice of white bread as the basis of their studies, stating that the amount a persons’ blood sugar goes up after eating one slice of white bread (which is almost completely pure carbohydrates) is a GI score of 100. All other foods are compared to that. Today they use the same test using a certain amount of drinkable glucose, which is a more precise serving than a slice of bread.
What does this matter? Well, I have at least 4 books on low carbohydrate eating, and “The New Glucose Revolution: Shopper’s guide to GI values 2006” by Dr. Jennie Brand-Miller and Kaye Foster-Powel said it best. “…Could carbohydrates be implicated in the development of obesity, are all carbohydrates the same, are all starches good for health and all sugars bad? To investigate, they began to study the effects of carbohydrates on blood glucose levels. They wanted to know which carbohydrate foods were associated with the least fluctuation in blood glucose levels and the best overall health, including reduced risk of diabetes and hart disease.”
They go on to explain that bad carbs are digested quickly in the stomach and release glucose into the bloodstream very quickly, while good carbs are digested more slowly and cause a more gradual raise in blood glucose.
There is more and more evidence that all of the major chronic diseases, including type II diabetes, heart disease, obesity, stroke, and even neurological diseases of the modern age are caused by the effects of a highly processed high carbohydrate diet, not from a high fat diet.
What is all this talk about whole foods? This is actually related to the Glycemic index, and this is actually the point I really want to make today: The more “whole” or unprocessed the food you eat the lower GI it has. The more processed the food you eat the higher the GI value usually is.
Case in point: from the “New Glucose Revolution” book mentioned above, let me list the same foods, just processed differently.
All breads list that the serving size is one slice, even to the pint that the serving size of a hamburger bun is ½ bun. Generally, the more fiber a food has in it the slower it is digested, and thus the lower the GI value.
White bread GI value 71
9 grain multigrain bread 43
Whole wheat 71
Whole wheat, stone ground 59
Sourdough wheat 54
Rye bread 51
Oatmeal (all made with water)
Instant oatmeal 82
Old-fashioned oatmeal 58
Steel cut oatmeal 52
This is an excellent case for eating the least processed variety.
White rice, depending on the type: Average GI 60 – 65
White rice, instant 87
Brown rice, quick cooking 80
This makes it look like the instant rice has a much higher GI value than the regular cooking rices, which makes sense if you think the instant rice is more processed and thus breaks down in your stomach faster. I have to note that the books also lists “glutinous rice, white, cooked” as having a GI value of 98 and Jasmine rice as having a GI of 109. No wonder I’ve always loved Jasmine rice! It’s insanely high in carbohydrates. And this simply makes the point that all carbs are not created equal, and even putting a GI value to foods doesn’t make eating and shopping that much easier. Although I do hope this article makes your understanding of the GI factor easier.