What is the Glycemic Index?
The Glycemic Index (GI) is a ranking of carbohydrate foods on a scale of 0 to 100 based on their effect on blood glucose (sugar) levels:
- Low GI: <55
- Intermediate GI: 56 – 69
- High GI: >70
High GI vs Low GI
High GI carbohydrates are quickly digested and absorbed, causing a quick increase in blood sugar levels followed by a quick drop. Carbohydrates with a low GI are a better choice as they are slowly digested and absorbed, producing a slow rise in blood sugar levels. This helps to give us long-lasting energy and keeps us feeling fuller for longer.
Lowering the GI of your diet can help to prevent and manage overweight and obesity, and reduces risks of type 2 diabetes, heart disease and some cancers.
|Category||Instead of these higher GI options||Swap with these lower GI options|
Dark or light rye
|Multigrain and seed breads|
Wholegrain high fibre wraps
White corn tortillas
|Breakfast Cereal||Refined puffed or flaked cereal|
Steel cut oats
Wholegrain or multigrain high fibre cereals
Medium grain white rice
Medium grain brown rice
|White or brown long grain rice such as Basmati|
Black or red rice
|Pasta & Noodles||Potato gnocchi|
Dried rice noodles
Fresh rice noodles
|Savoury Snacks||Rice crackers|
Dry roasted chickpeas
Vegetable sticks with hommus
|Milk & Yoghurt||Rice milk|
Small fruit smoothie
Rice malt syrup
Brown rice syrup
What about Glycemic Load?
The Glycemic Load (GL) looks at both the GI of a food and the amount of carbohydrates per serve to give a better picture of the effect of a food on blood sugar levels. For example, although pasta has a low GI, a large serving can still cause a quick rise in blood sugar levels due to the overall amount of carbohydrates eaten.
The GL of a food can be classified as low, medium or high:
- Low: ≤10g
- Medium: 11 – 19g
- High: ≥20g
GL is calculated using the following formula:
For example, an apple has a GI of 38 and contains 13g of carbohydrates.
GL = 38 x 13 / 100 = 5g (low GL)
The higher the GL, the greater the expected rise in blood sugar levels, so like GI, foods with a lower GL are preferable.