Chapter 6: “Doc, can you explain what glycaemic index (GI) is?”

Studies have now shown that the blood glucose level soon after eating is a good indicator of the risk of developing diabetes, rather than the blood glucose level over a long period of time.

Testing of foods have also shown that there are some food that increase the blood glucose level to a very high level soon after eating while there are other foods that do not cause such a dramatic increase in the blood glucose. The potential of the food to increase the blood glucose is reflected by the glycaemic (pronounced gly-see-mik) index (GI).

The GI ranking is for carbohydrate foods only and is ranked from 0 to 100. A food with a GI index of 70 or more is considered high. That means these foods increase the blood glucose level to a very high level after eating. A GI of 56 to 69 is medium and GI of 55 or less is low.

Patients with diabetes should eat foods with low GI. This will help them control their glucose level after eating (postprandial hyperglycaemia). Low GI foods also help reduce weight and do not make you feel hungry quickly thus controlling appetite.

Just like the Heart Foundation Tick symbol, manufacturers pay a fee to participate in the GI symbol program (See figure 3.0). This program is a nonprofit public health initiative led by the University of Sydney.

The program also involves Diabetes Australia and the Juvenile Diabetes Research Foundation. Foods displaying the GI symbol must also meet strict nutritional guidelines for kilojoules, total and saturated fat, sodium, fibre and calcium.

It is also important to note that not all low GI food will display the GI symbol. Foods that claim a low GI but do not display the GI symbol must have their nutritional panel checked for other nutritional content such as fat and salt (sodium) before deciding to buy the product. Traditional PNG foods such as kaukau, taro and banana are of medium to low GI. Sugar cane which has a lot of fructose has a high GI.

Figure 3.0. Foods with this symbol have been tested for strict nutritional guidelines by University of Sydney.

GI Symbol



About rodney itaki

I am a medical doctor from Papua New Guinea. My posts focuses on current and emerging health issues in PNG.
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4 Responses to Chapter 6: “Doc, can you explain what glycaemic index (GI) is?”

  1. Dianna Crisp says:

    Hi Rodney

    Thank you for mentioning the GI Symbol. We have updated our logo to allow easier idetification of Low GI foods that have been tested and meet the nutritional criteria. Please go to to view and for any further information. Thanks

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