The glycaemic index (GI) is a system of ranking carbohydrate foods, based on their effect on our blood glucose (or blood sugar) levels. The GI ranks foods from 0 to 100. The higher the GI value, the greater the blood sugar response. So, low GI foods raise blood sugar levels just a little, medium GI foods raise blood sugar levels moderately, and high GI foods raise blood sugar levels quite high and quite quickly.
The ranking of GI foods is as follows:
- Low GI foods - less than 55.
- Medium GI foods - 55 to 70.
- High GI foods - more than 70.
Which foods are low GI?
Foods with a low GI result in a small rise in blood sugar levels.
GI levels of different foods
|Food||Low GI (GI < 55)||Medium GI (GI > 55 and < 70)||High GI (GI >70)|
|Bread||Multigrain bread, special Low GI white breads, sourdough bread||Pita bread, rye bread||White/wholemeal bread, crumpets, English muffins, pikelets, plain scones|
|Grains/Pasta||Pasta, Barley, cracked wheat, noodles, brown rice||Doongara rice, Basmati rice||Calrose and Jasmine reice, rice cakes water crackers, puffed crispbread|
|Cereal||Natural muesli, rolled oats, high fibre breakfast cereals||Low fibre cereals like rice crisp cereal, corn flakes|
|Vegetables||Corn, carrots, sweet potato, lentils, chickpeas, kidney beans, baked beans||Beetroot||Potato (including baked, mashed, steamed & boiled), swede and parsnip|
|Fruit||Apples, oranges, strawberries, mangoes, pears, peaches||Apricots, pineapple, kiwifruit, bananas||Watermelon|
|Dairy||Milk, yoghurt, ice cream, custard|
How do I know what the glycaemic index (GI) of a food is?
There are books and websites which list the GI of foods including: www.glycemicindex.com, ‘The GI Factor’ and ‘The Glucose Revolution’ by Dr Jennie Brand Miller et al.
Why should I eat low GI foods?
- Low GI foods result in a smaller rise in blood sugar levels. This is especially beneficial to people with poor blood sugar control.
- Low GI diets can help people lose weight and lower blood fats.
- Low GI diets can improve the body´s use of insulin, a hormone released by the pancreas to help utilise the glucose from the food we eat.
How do I lower the GI of my diet?
To eat a lower GI diet, there is no need to eat only low GI carbohydrate foods. Simply substitute one high GI food that you would normally eat (e.g. potatoes, white bread or instant rice) with a low GI food (e.g. pasta, whole grain bread or Doongara rice) at each meal.
Should I eat only low GI foods?
No. High GI foods add variety to our food choices. The aim is to incorporate at least one low GI food at each meal, to lower the overall GI of the meal. High GI foods are useful for some groups of people, such as athletes, who need a fast supply of glucose to fuel their muscles during and after competition.