The glycemic index is a way to measure and select complex carbohydrates and low-carbohydrate foods in your diet. These foods are believed to be beneficial to your health as they release glucose relatively slowly during digestion. People with diabetes and a range of other medical conditions will, on occasion, use a diet based on the glycemic index to prevent or control symptoms.
History
The concept of a glycemic index (GI) for diet control was defined by a group of researchers at the University of Toronto. Led by Dr. David J. Jenkins, the researchers found a method of ranking and classifying the carbohydrates in foods in accordance with each food's effect on blood glucose levels. Foods are ranked on a scale of zero to 100, with low-GI foods having a rating lower than 55. Medium-GI foods are those rated between 56 and 69, while a GI value of 70 or more designates a high GI food.
Function
The index allows individuals to select low GI foods for a steady release of glucose into the bloodstream (ref 1-3). High GI foods cause a quick glucose rush to the bloodstream upon consumption and digestion of the food, which is considered less desirable in terms of overall health. A slower glucose release increases your sense of satiety or fullness after eating, and can help keep energy levels balanced throughout the day (ref 1, 2).
Benefits
The glycemic index was designed for people with diabetes, and is believed to be beneficial for diabetic blood sugar control. According to MayoClinic.com, a low-GI diet may reduce the need for diabetes medication, and works to reduce insulin resistance. The official website of the Glycemic Index, which is published by University of Sydney, states that use of the index can reduce the risk of developing heart disease, heart attack or stroke. Additionally, use of the index has been credited with reducing the symptoms of polycystic ovary syndrome, or PCOS.
Types
Typical foods consumed on a low-GI diet include most fruits and vegetables, whole grains, meats, dairy products, nuts and low-carbohydrate foods. Foods high in refined sugar, and simple carbohydrates such as white bread, rank higher on the glycemic index and therefore would be avoided on a glycemic diet.
Warning
The perceived health benefits of a diet governed by the glycemic index have not been conclusively proven in scientific studies. Although some individuals have found the diet helpful for weight control and diabetes control, individual reactions to such a diet will, of course, vary. You should always seek medical advice from your own primary care physician before making any major changes to your diet.
