What is Glycemic Index?

Foods are ranked on the basis of how they affect the glucose levels in our blood. The glycemic index indicates the amount by which the glucose in the blood is increased after food is consumed.

The index measures only foods known to be rich in carbohydrates. The glucose levels in the blood are not affected much by foods rich in protein or fat.

It is a common opinion that what needs to be avoided is table sugar. In the past, the experts supported this opinion, but it was proven lately that some complex carbohydrates can affect to the worse.

The glucose levels in our blood are kept under control if the glycemic index is used for the preparation of meals. This is extremely important for people suffering from diabetes. This new concept in nutrition is also taken into account by overweight people and athletes who benefit from it.

The complications that diabetes can lead to are best avoided by people who suffer from diabetes and can keep their glucose blood levels controlled. Regular daily exercise, high fiber diet, and small amounts of saturated fat are what most experts recommend to diabetics.

It is an excellent advice to exercise, consume more fiber, and reduce fat, but the main problem lies in the carbohydrates. It is a widely accepted opinion that for people with diabetes, the high-carbohydrate diet is best. However, because of the fact that glucose in the blood is raised to high levels through the carbohydrates, experts like Dr. Richard Bernstein favor the low-carbohydrate diet.

Some carbohydrates act differently from others. They are not easily broken down in the intestine and so, they are not causing the rapid rise of glucose levels in the blood. Their glycemic index is high. Though the GI index shows the speed of carbohydrate to glucose conversion, it doesn't indicate how much of the carbohydrate is present in the food.


An extension to the GI, considered to be of prime importance, is known as the glycemic load. It takes the available carbohydrates quantity into account. Carbohydrates like sugar and starch provide energy and are referred to as the available carbohydrates. The GI of the food and its effect, measured in grams of carbohydrates in a standard meal, is the way the glycemic load is calculated. This concept was developed in Harvard in 1997 by the researcher and professor Walter Willet, M.D. He and his associates made a number of article publications on the subject. It was, however, not before they published an article in Harvard Women's Watch that GL numbers were quoted. The GL was calculated for a short list of few foods while the low GL and high GI of the watermelon were noticed. Up till now, the GL of 750 foods has been calculated by Jenny Miller and her University of Sydney's Associates.

Prior to the development of the GI, it was assumed by scientists that the human bodies are able to absorb and digest simple sugars in a fast manner. The glucose levels in our blood are thus increased rapidly. This fact constitutes the basis for the advice of the American Diabetes Association to avoid sugar.

We are now aware that some complex carbohydrates can force our glucose blood levels to rise even faster. Simple sugars, however, supply enough calories so they should be avoided.

The GI results proved to be a surprise for many with baked potatoes, for example, having a GI much higher than that of the table sugar.

So far, the scientists have calculated the GI indexes of 750 foods high on carbohydrates. The idea is to consume fewer foods, known to have a high GI and more of those with low GI.

The usefulness of the GI is best demonstrated by people who suffer from diabetes and are willing to base their diets on the right food, thus minimizing the risks of spikes or high glucose blood levels.