Glycemic Index Low Down

Glycemic DietThe glycemic index or GI gives an indication of how fast a food that contains carbohydrate, affects our blood glucose levels. All carbohydrates are not equal. There are those that are digested and absorbed slowly over about 3 hours and those that spike blood glucose levels almost immediately.

Low glycemic index foods take about three hours to be digested and absorbed and thus supply the body with a steady source of fuel (glucose) for up to three hours.

High glycemic index foods, on the other hand, invariably spike blood glucose levels, resulting in higher insulin levels that encourage fat storage, irritability and reduces cognitive function as the body tries to rectify the high blood glucose levels.

Visit for a comprehensive list of GI and GL values of many foods.

The World Health Organisation (WHO), the highest nutrition authority in the world, has recently stated that all people should eat a high carbohydrate diet based on low Glycemic Index (GI) foods. The GI is determined by actual tests and does not rest on assumptions of what effect a product has on blood glucose.

To look up the GI values of most commonly eaten foods, use The South African Glycemic Index and Load Guide by G Steenkamp and L Delport (GIFSA, 2010). It is available from most book stores, some pharmacies and from the websites or



  1. says

    Re: “High glycemic index foods, on the other hand, invariably spike blood glucose levels” – not true – what matters is NOT the glycemic index of the food but the glycemic load of the meal or snack – eating a small piece of watermelon for example which has a high glycemic index (70+) will not “spike blood sugar levels” because the amount of carbohydrate consumed is small. ¬†Conversely, excessive amounts of low glycemic foods can cause unwelcome spikes in blood sugar levels if eaten in very large quantities.

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