Glycaemic Load (GL)
Glycaemic Load is a new measure for assisting in making healthy food choices by being able to compare foods using a combination of the Glycaemic Index of the food and the amount of carbohydrate in the food. This measure gives an estimate of the relative glycaemic effect a food has on blood glucose expressed as Glycaemic Glucose Equivalents (GGE). If a portion of food has a GGE value of 8, it means it would have about the same effect on blood glucose as 8 g of glucose.
The following example explains how GL is more accurate than GI when presented with foods of different serve sizes and carbohydrate content. An average 58 g apricot and a 128 g banana have Glycaemic Indexes of 57 and 58 respectively. However, because a banana contains more carbohydrate and is twice the size of the apricot it will raise blood glucose levels six times higher than an apricot. This real difference in the glycaemic effects of a banana versus an apricot is reflected in their GL values; the GL of the 58 g apricot is 3, while the GL of the banana is 18. Hence the GL gives a better indication of the impact of the food item on blood glucose levels.
There are three categories of GL which foods can be classified into and a balanced diet should contain foods from all of these.
Low GL, but high carbohydrate foods assist in making you feel fuller for longer due to a lower and more sustained increase in blood glucose levels. This assists in controlling weight by making you feel less like snacking between meals. Including carbohydrate foods in the diet that give low blood glucose responses improves insulin sensitivity and decreases the risk of diabetes. Low GL foods are classified as containing 0 to 10 GGE/100g and examples are Multigrain bread (5), WeetBix (7) and raw apple (5).
Medium GL foods range from 11 to 19 GGE/100g and examples are Bread (Fibre white) (10), Molenberg Bread (10) and fresh orange juice (12).
High GL foods contain 20 GGE/100g or higher and examples are plain bagel (25), toasted sweetened muesli (25), and canned apricots (47). Diets containing large amounts of high-GL food have been associated with increased risk of diabetes and heart disease. For people with Type 2 diabetes, consuming a low-GL diet is one method of controlling their diabetes and general health as low-GL foods put less pressure on the requirements for insulin.
However an example of how low GL and high GL foods are an important part of a person’s diet is when you consider the requirements of a sports person. Sports people consume low-GL foods before an event to delay the time it takes to reach exhaustion point. However they also consume high-GL foods to reduce fatigue during an event and to help with recovery time afterwards.
Glycaemic Load offers a guide to choosing a variety of food combinations to make up a balanced diet and give a measure of the relative impact the food will have on blood glucose levels.