The glycemic index has been used very successfully by many individuals for weight loss and regulating blood sugar levels over the past few years but should you be considering the glycemic index or the glycemic load?
The Glycemic Index (GI)
Whenever you eat a food that contains carbohydrate this will have an effect on your blood glucose levels. Some carbohydrates are digested and absorbed quickly, leading to a substantial increase in blood glucose levels. Other carbohydrates tend to be digested and absorbed much slower and therefore cause a trickle of glucose into the blood stream. This means that blood glucose levels do not increase rapidly. The GI is a measure of how quickly a carbohydrate is digested, absorbed and released into the bloodstream. Ideally we need to keep our blood glucose levels stable by consuming low GI carbohydrates.
The Glycemic Load (GL)
The GL is a measure that is based on the following calculation: GL = (GI x the amount of carbohydrate (grams)) divided by 100. The GL indicates the quantity and quality of carbohydrate in a food. When you only consider GI you tend to neglect how much carbohydrate is actually in the food. The GL takes into account the glycemic index and the amount of carbohydrate. The GL can be a good tool as often foods may seem to have a high GI but in fact still be healthy. Watermelon is a great example of this as it has a high GI (72) but only has 6 grams of carbohydrate per serve. By calculating the GL your will see that the GL is 4 (72 x 6) /100 = 4 – and this is considered low.
So what should you use?
High GL foods will have a higher content of carbohydrate, and a higher GI. The foods which tend to have a low GL have less carbohydrate and a low GI. This often means that foods such as cheese are considered low GL, when in fact they are not considered to be a carbohydrate food. This means that if you simply focus on GL your diet may not be ideal and may contain too many fatty foods. The University of Sydney Glycemic Index Research Group suggests that you should continue to use the GI for this reason. They suggest that you choose at least one low GI food at each meal, be careful with your portion sizes of high carbohydrate foods and think about including slow carbs and avoiding a no carb foods. Using the GI is also simpler as you do not have to factor in more calculations when you are choosing a food product.
If you would like more information on glycemic index and glycaemic load contact a dietitian or nutritionist.
Originally published on Nov 15, 2011
