What is glycemic index (GI) and why it’s important, especially for people with type 2 diabetes?
The glycemic index
The glycemic index represents the rise in a person’s blood sugar level two hours after consumption of the food. The GI is a number associated with the carbohydrates in a particular type of food that indicates the effect of these carbohydrates on a person’s blood glucose (blood sugar) level. In other words, it is a scale that ranks carbohydrate-rich foods by how much they raise blood glucose levels compared to a standard food.
The glycemic index classification
The glycemic index is useful for understanding how the body breaks down carbohydrates and takes into account only the available carbohydrate (total carbohydrate minus fiber) in a food. Glycemic index does not predict an individual’s glycemic response to a food, but can be used as a tool to assess the insulin response burden of a food.
- Standard GI: A value of 100 represents the standard GI, an equivalent amount of pure glucose.
- High GI (70 and above): Foods with carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream tend to have a high GI. A lot of starchy foods have a high glycemic index.
- Low GI (55 or less): Foods with carbohydrates that break down more slowly, releasing glucose more gradually into the bloodstream, tend to have a low GI. A lower glycemic response usually equates to a lower insulin demand and can improve long-term blood glucose control and blood lipids.
The glycemic index concept was developed by Dr. David J. Jenkins and colleagues in 1980–1981 at the University of Toronto in their research to find out which foods were best for people with diabetes.
Why the glycemic effect of foods is important?
Eating foods with a low GI decreases your risk of developing heart disease and type 2 diabetes. It may help you to control your blood sugar level, cholesterol level, your appetite, and your weight.
The glycemic effect of foods depends on a number of factors. The major factor is a combination of three constituents in a particular food:
- the type of carbohydrate and its amount
- the fatty acids profile
- the protein content
Foods low with Glycemic Index
- Nuts and seeds contain very small amounts of carbohydrates. The glycemic index for all nuts and seeds is very low (typically between 0-20).
- Beans: black, pinto, kidney, lentil, peanut, and chickpea
- Whole intact grains: wheat, millet, oat, rye, rice, barley
- Vegetables and mushrooms
- Most sweet fruits: peaches, strawberries, mangos, and etc.
However, it doesn’t mean that you can eat foods with a low GI as much as you want. The glycemic index helps you to make informed food choices. It is only one part of healthy eating. Healthy eating means choosing different foods from all food groups; including foods high in fibre; eating with moderation; reducing the amount of fats, sweets and salt.