The Glycaemic Index (GI) can help people with diabetes decide the type and quantity of foods to eat to manage their condition. To put it simply, GI is a measure of how quickly the food ingested raises blood glucose levels after eating. The glycaemic response of a food is affected by the type and amount of carbohydrate consumed.
The GI ranks the carbohydrates contained in food on a scale from 0 to 100. Foods with a high GI are more easily absorbed and digested and tend to raise blood glucose levels faster. Foods with a low GI are digested more slowly and have a lower impact on blood glucose levels.
Typically (but not always), foods containing simple sugars and higher amounts of processed ingredients have a high GI, and foods rich in fiber, protein, and fats have a low GI.
- Foods with a GI of less than 55 are considered low GI foods. These include fibrous fruits and vegetables, whole beans and legumes, low-fat dairy products, nuts, and whole grains.
- Foods with a GI between 56 and 69 are considered moderate GI foods. These include starchy foods like potato, sweet potato, white rice, corn/maize and couscous.
- Foods with a GI higher than 70 are considered high GI foods. These include cakes, confectionery, white bread, doughnuts, etc
The GI system also reveals the nutrient density of foods that are consumed. High GI foods cause glucose molecules to rush through the bloodstream, making it harder for the body to manage them. It is therefore recommended to:
- Eat more whole grains, fruits, vegetables, legumes, and nuts
- Eat fewer starchy vegetables and foods
- Include as many fresh and colorful vegetables in your regular diet
- Avoid processed and sugary foods such as cookies, sweets, etc.
The glycaemic response of a meal can be controlled by limiting consumption of high GI foods and/or consuming foods that are naturally low in GI. Factors that can impact the GI of a meal include the way it is prepared, the different ingredients included and their ripeness.