First of all, the name ‘glycaemic’ is derived from the medical term ‘glycaemia’ meaning ‘the presence of glucose in the blood’. All CARBS receive a glycaemic index (GI) score from 1 to 100. The lower the number the better - or should I say, ‘less horrible’. A score of 1 is the lowest and slowest and 100 is the highest and fastest to convert CARBS to glucose (a type of sugar). Therefore, pure glucose obviously scores 100. However, it is not as black and white as the GI score might suggest, as it assumes we are only eating the food being scored in isolation and not combining it with other foods, which when bound together after digested may change the speed of conversion into sugar.
The other limiting factor of GI is that it doesn’t look at portion sizes. There are some items with a fairly low GI score, where the portions sizes are by definition big and therefore still not recommended if we are either trying to lose weight or stay healthy. A more reflective index is the glycaemic load (GL). While GI is useful to know how quickly glucose will enter the bloodstream, the GL informs us how dangerous that load will be.
The GL index is calculated simply by multiplying the typical grams of carbohydrates in a serving by the GI index for that type of CARB and then dividing it by 100. For an easy and comprehensive list, I have added a combined GI & GL chart below.