The Glycemic Index

By Professor Jack A. Bateman

The glycemic index (GI) is a measurement method that quantizes the blood glucose levels that follow the consumption of a given food source of carbohydrate. -The higher the blood glucose level raises after the consumption of a carbohydrate source, the greater the stimulation to produce insulin. Elevated insulin levels not only promote glucose transport into cells, but it stimulates cells to produce fat. Denovo fat production in human body cells only produces saturated fat. Saturated fat levels in the body have been research linked to many degenerative diseases, including diabetes, heart disease and cancer.
The glycemic index of a given food is determined in the laboratory by measuring the fasting glucose blood level in a human, then feeding the person a measured amount of a carbohydrate food. Two hours after consumption (post prandial) of the carbohydrate food another blood glucose level is determined. The blood glucose elevation is compared to the elevation caused by the consumption of either 100 g of glucose or the equivalent amount of white bread. This generates a comparative number that is called the glycemic index. Glucose and white bread are both used as standards, therefore there are two sets of values for the glycemic index. The glucose standard based values are lower than the white bread standard based values. GI is an assessment of the quality of a carbohydrate food.
Thousands of studies have lauded the benefits of eating a low glycemic index diet. The research findings include lower fasting blood glucose level, improved glucose tolerance, marked decrease in glucose resistance, decreased insulin response, a decreased blood lipid profile, decrease incidence of metabolic disease (a syndrome leading to diabetes and heart disease). Even though there are doubting Thomas’s who question the validity of the glycemic index, many researchers continue to publish journal articles showing correlations between a low glycemic diet and decreased risk of diabetes, heart disease and some cancers.
Another calculated value is currently being used to categorize and judge carbohydrate foods is the glycemic load (GL). GL is calculated by multiplying the GI divided by 100 times the grams of carbohydrate in the given food or drink. For example, Coca Cola has a GI of 63. 250 ml of Coca Cola contains 26 grams of carbohydrate. This calculation gives a GL of 16. The lower the GL the better the food source of carbohydrate is on your health. GL values in the high teens and above are less desirable than single digit values. A white bagel has a GI of 69, with a GL of 24. In contrast to whole grain pita bread that has a GI of 73 and a GL of 9. A boiled white potato has a GI of 78 and 136 grams has a GL of 21. In contrast, kidney beans have a GI of 24 and 136 grams has a GL of 6.7.
Glycemic index (glucose standard) values of 54 and up are considered high. GI values of 43 and below are considered low. Values in between are considered moderate. Low glycemic index foods include: legumes (beans and some nuts), most fruits, most dairy products, most pastas, fructose, and some whole grain products. Most low GI foods tend to contain high fiber content. High GI foods include: many cereals, most rice, most single grain breads, corn and potatoes, most snack foods, most deserts, glucose, sucrose and some fruits.
The glycemic index and its new cohort, the glycemic load are excellent tools in the selection of healthy carbohydrate foods in ones personal nutritional plan. Low glycemic index choices can decrease the person’s risk of developing degenerative diseases as well as the maintenance of a healthy body mass index.
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