We’ve become too lackadaisical about our food. It’s far too easy to poke a coin into a machine or drive up to a window for something is the form of food to consume. Consider this. Should blood glucose levels rise above 180 mg/dL (a measurement of glucose in the blood stream), for a prolonged period of time, kidney failure, blindness, and hardening of the arteries can result. If one’s blood sugar drops below 40 mg/dL, coma, seizure, or even death may occur. Therefore, our bodies have a sophisticated hormonal system that is continuously working to maintain blood sugars in the optimal range, which would be between 80 mg/dL and 180 mg/dL.
There are two major hormones, which are primarily involved in controlling blood sugars. Insulin lowers blood sugar and is essentially our "storage hormone" and drives the sugar into the cell to be utilized or stored as fat. Glucagon is the opposite hormone of insulin and essentially takes stored fat and changes it into sugar as means of increasing blood sugar levels. Amazing findings are being revealed about what takes place in our bodies when we eat what is now referred to as a high glycemic meal. We now know why so many Americans and people who live in industrialized countries are becoming overweight, diabetic, and having heart attacks.
All carbohydrates are simply long chains of sugars: they are digested and converted to glucose. Since the early 1900’s, it was believed that the digestion rate and conversion to glucose was directly related to the length of the chemical sugar chain. This gave rise to the terms "complex carbohydrate" and "simple sugar," a limited concept leading dieticians and physicians alike to recommend the consumption of starchy foods along with a decreased consumption of sugar.
In the early 1980’s, however, the concept of chain length in carbohydrate digestion rate was questioned. Since then, many researchers have focused on how fast specific carbohydrates are absorbed by the body and converted to sugar, thus determining the body’s insulin response.
Many researchers now propose the use of the glycemic index—the rate of how fast blood sugar levels are raised after a particular carbohydrate is consumed—as a system for classifying foods containing carbohydrates. This concept was thoroughly reviewed in a major article, which appeared in the May 8, 2002 issue of the Journal of the American Medical Association titled, "The Glycemic Index", written by David Ludwig, M. D. This article draws heavily on Ludwig’s findings.
Glycemic index is determined by the rate the blood sugar rises following the ingestion of a particular carbohydrate when compared to a control (usually straight glucose). Glucose is usually given a glycemic index of 100. Therefore, all other carbohydrates are compared to the absorption and rate of blood sugar increase following the ingestion of glucose. Table 1 lists a sample of a few carbohydrates and their glycemic index. Many studies use white bread as their control, which has a glycemic index of 70 when compared to glucose. This has created significant confusion and variation in the glycemic numbers. I have chosen to use glucose as the standard, since this is the control being used in most of our medical studies. Table 1 also lists a new concept known as the Glycemic Load.
The glycemic load is defined as the weighted average glycemic index of the individual food multiplied by the amount of calories the food actually contains. A particular carbohydrate may have a high glycemic index but is low in calories, like carrots, or they may have a high glycemic index and a high in calories, like potatoes. Some carbohydrates like peanuts have a low glycemic index and a low glycemic load. In general, most refined starchy foods and highly processed foods have a high glycemic index, whereas whole foods like fruits, vegetables, and legumes tend to have a low glycemic index.
Table 1 Glycemic Index and Glycemic Load Values of Representative Foods