Why Glycemic Index Matters
While many of us are focused on how much sugar is in food, we really should
be focused more on Glycemic Index (GI) – especially if we have type 2
The Glycemic Index (GI) is a measure of how quickly or slowly a
carbohydrate food is digested and increases blood glucose levels.
The rate at which a food is broken down in your body during digestion is a
lot more relevant to your health than whether the food contains sugar or
In fact, some foods that contain sugar are digested more slowly than some that
don’t contain any sugar at all, and that has flow-on effects to your
energy levels, mood, concentration and weight.
HIGH VS LOW GI
High GI foods are broken down into sugars very quickly, causing a ‘spike’ in blood
glucose levels, usually followed by a ‘crash’ soon after eating. This
can contribute to slumps in energy levels, mood, concentration, and
cause cravings for sugary foods.
The sudden rise in blood glucose levels puts pressure on your body to
produce more insulin, which over time can lead to type 2 diabetes.
Glucose spikes can damage arteries and blood vessels, thus increasing
your risk of heart disease.
A high GI intake can also increase your risk of fatty liver, certain cancers and if you have type 2 diabetes, negatively affect eye sight.
foods are also not helpful for weight control. Significant blood
glucose level peaks are followed by big drops, which stimulate hunger,
often sending you in search of more ‘quick fix’, high-GI foods and
generally encouraging you to eat more.
Foods with a GI of 55 or lower are considered low GI.
Low GI foods break down and release their sugars more slowly, providing a more sustained
source of energy. They are not only relevant for those with diabetes and
watching their weight, but can benefit everybody.
Eating a low GI intake can:
- Help control blood sugar and insulin levels
- Reduce your risk of cardiovascular disease and type 2 diabetes
- Reduce your risk for certain cancers, including endometrial, breast, colon and ovarian cancer
- Reduce LDL cholesterol levels
- Reduce the risk for hemorrhagic strokes in women
- Encourage fat-burning during exercise
Do I need to eat only low-GI foods?
Looking at the GI of a food can help you make healthier food choices, but you will also need to consider:
- Being more mindful of your food portion sizes
- Some low-GI foods are high in saturated fat (for example. dark chocolate, pizza and potato chips)
- Some higher-GI foods contain important nutrients and don’t need to be avoided (such as watermelon and polenta).
GI of a food can change when you combine it with another food. For
example, wholemeal bread can have a medium-high GI, but a smear of
peanut butter will lower the overall GI.
HOW DO I KNOW IF IT’S LOW GI?
Below we’ve ranked some common foods by GI. However keep your eyes peeled for the Low GI Certified symbol on product packaging when shopping.
The symbol was created by the GI Foundation, a non-profit organisation
supported by The University of Sydney and Diabetes NSW & ACT, to
appear on food packaging to make it easy to identify low GI products. It
can be found on a wide range of supermarket foods. They have also
developed a Low GI Recipe symbol for recipes that are low GI and meet
International Dietary Guidelines.
GI OF COMMON FOODS
- Watermelon 72
- Cherries 66
- Pineapple 59
- Banana 52
- Apple 38
- Cornflakes 77
- Weet-Bix 69
- Special K 56
- All Bran 44
- Porridge (rolled oats + milk) 42
- Wonder White 80
- Country Life gluten-free multi-grain 79
- Wholemeal bread 74
- Buttercup fruit and spice loaf 54
- Burgen Soy Lin 52
- Couscous 65
- Maggie 2-minute noodles 46
- Egg fettuccine 40
- White spaghetti 38
- Wholemeal spaghetti 37
- Jasmine white rice 89
- Brown rice 68
- SunRice Medium Grain Brown Rice (microwaved), 59
- Basmati rice 58
- Long grain white rice 50
The GI of a food is definitely worth considering – but there’s no need to
avoid nutrient-dense foods with a high GI. Nor is it a good idea to eat
as much of a food as you like, just because it has a low GI rating –
particularly if you are watching your weight, or if you’re concerned
about your blood glucose or insulin levels.
Overall, low-GI foods should be used to supplement other
healthy eating guidelines, including eating plenty of fruit,
vegetables, wholegrain breads and cereals, and to limit foods high in
saturated fats and added sugar.
If you want to know more about the benefits of a low GI-dietary intake,
the GI Foundation website is a great resource. It also offers helpful
information about managing diabetes and blood glucose levels, and
provides low GI recipes and a meal plan to get you started.