The Glycemic Index is a numerical Index that ranks carbohydrates based on their rate of glycemic response (i.e. their conversion to glucose within the human body). Glycemic Index uses a scale of 0 to 100, with higher values given to foods that cause the most rapid rise in blood sugar. Pure glucose serves as a reference point, and is given a Glycemic Index (GI) of 100.
Glycemic Index values are determined experimentally by feeding human test subjects a fixed portion of the food (after an overnight fast), and subsequently extracting and measuring samples of their blood at specific intervals of time. The earliest known work on the Glycemic Index was done by Dr. David Jenkins and associates at St. Michael’s Hospital in Toronto, Canada. More recently, an effort to expand the Glycemic Index has been made by Jennie Brand-Miller and her associates at the Human Nutrition Unit of the University of Sydney in Sydney, Australia.
The Glycemic Index Yields Some Surprises
Nutritionists used to believe that all simple sugars digested quickly and caused a rapid rise in blood sugar, and that the opposite was true for “complex carbohydrates”. But that’s not always the case. While many sweet and sugary foods do have high GI’s, some starchy foods like potatoes or white bread score even higher than honey or table sugar (sucrose)!…