Glycaemic Index Definition

The Glycaemic Index - An Introduction.

The Glycaemic Index, or GI, is a way of ranking carbohydrate foods according to their effect on blood glucose. Foods with a low GI (such as whole grains, pasta and fruits and vegetables) make our blood glucose rise and fall gently, resulting in the body feeling fuller for longer.

A low GI diet is therefore appropriate for diabetics, dieters and endurance athletes. High-GI foods (such as white bread, potatoes and watermelon) are broken down quickly by our bodies and cause the blood glucose levels to surge and then crash. This diet would be suitable for post-endurance exercise energy recovery.

Some nutritionists now think surges in blood glucose can affect our long-term health. Glycemic index values for different foods are calculated by comparing measurements of their effect on blood glucose with an equal carbohydrate portion of a reference food. The current scientific validated methods use glucose as the reference food. Glucose has a glycemic index value of 100.

So, GI values can be seen as percentages and are commonly interpreted as follows:

• Low GI - less than 55
• Intermediate GI - between 56 and 69
• High GI - higher than 70