The glycemic index was developed with the express purpose of helping people with medical conditions such as diabetes learn what foods to avoid and what foods are safe. Reduced to its simplest terms, the index tells users how quickly a given food will break down by the digestive process and release glucose into the bloodstream.

Foods that are high on the index, such as watermelon and white bread, are digested quickly and release their glucose in a very rapid fashion. Other foods, such as most fruits and vegetables and certain types of grains, release their glucose in a slower fashion and are thus considered to be low.

The concept of the glycemic index, often abbreviated "GI," began to form at the University of Toronto during the early 1980s. Dr. David Jenkins was one of the key people who developed the system. He developed it primarily as a tool for helping diabetics deal more effectively with their disease. Jenkins developed an entire diet around the index list of foods.

Many who are learning about the glycemic index for the first time will be shocked to learn where different foods fall on the GI spectrum. There are also some surprises to be had in consideration of different foods that are normally considered to be very healthy. For example, avocados are a low glycemic index food. However, figs and dates are high on the index.

A great example of a food that most people would think might be high on the it is cherries. However, as it turns out, cherries are very low on the glycemic index as are most nuts. In fact, nuts can have some of the lowest numbers on the entire index. These are just a couple of surprises that can be found on the it. Part of the importance of this method of looking at foods is that it can reveal a great deal of information quickly about what we eat. The glycemic index can even shed some light on what foods are good for us and which ones are not.

While the glycemic index clearly can tell us how we can improve our overall health through low glycemic foods, it also has the added benefit of telling us what foods to avoid. Foods that are high on the GI include white bread, baked potatoes, breakfast cereals, as well as many corn and rice products. Foods such as white bread and baked potatoes are very high on the index list. There are medical studies that indicate that a diet high in these foods may not only be unhealthy, but can even promote disease over a long term period.

Since, its initial development, this system has been used to help thousands of diabetics across the world and even has been adapted for use in the dieting. There have been diets created specifically around the glycemic index that guide dieters towards foods low on the index list and help dieters find alternatives to high glycemic food choices.