GLYCEMIX LOAD INDEX

Q. I have read mixed reviews about the importance of following a low glycemic diet and how it will help to regulate my blood sugar levels. Can you explain?

A. Glycemic Index and Glycemic Load; The Glycemic values of foods no longer apply to the diabetic population, alone. More and more we are understanding the numerous and powerful health benefits of eating a low glycemic load diet and how it applies to all of us.

Glycemic load (GL) and glycemic index (GI) are two methods of ranking a food based on the impact they will have on blood sugar. Diets consisting of foods that have a high glycemic load have been independently associated with increased risk of developing type II diabetes, cardiovascular disease and certain cancers. Similarly, research also confirms that a low GI diet may help to protect against obesity, colon and breast cancers, among other numerous health benefits.

The difference between GI and GL
Glycemic index is the numeric ranking of carbohydrate containing foods based on their potential to raise blood sugar. They are ranked via their impact on blood sugar compared to a test food (usually glucose itself, or white bread). Glycemic load ranks foods based on how high they will raise blood sugar after a specific amount of a specific carbohydrate. GL is measured by multiplying the GI with the dietary carbohydrate content of a specific food. The total is then divided by 100. To illustrate the difference between GI and GL, I'll use a carrot. The GI will give you a rating for how quickly the carbohydrate found in carrot will raise blood glucose post consumption, while the GL will index how much a whole carrot (which in one carrot is actually only a small amount of carbohydrate, combined with fibre, water, antioxidants, etc.) will raise blood sugar. GL is therefore a more practical and useful tool for most individuals looking to get the most health benefit out of their diet.

Foods that alter your GI or GL
Something else that we need to consider is that these ratings are all based on the effect these foods have when consumed alone, not in the presence of other carbohydrates, fats and protein. When consumed as part of a meal, the total impact of both the glycemic load and the glycemic index goes down. In this sense, we can alter the glycemic value of a meal. If you absolutely must eat that white potato (high on the glycemic index) make sure to pair it with other foods that are ranked low. This way the meal averages out to be somewhere in the middle. There are a variety of lists available online that will be able to give you a GI or GL index of a wide range of foods. As a general rule, any white food (white bread, white rice, white flour, white sugar, white potatoes) are considered high. Foods high in fibre or protein tend to be lower in glycemic index and load values, as do healthy fats such as olive oil, flax seed, fish/fish oil and nuts/nut oils.

So what numbers are we looking for?
In terms of GI, anything ranked below 5.5 is considered low and anything above 7 is considered high. In terms of GL, anything less than 10 is low, between 11-19 is medium and anything 20 or more is considered high.

In general, it pays to have a rough idea of how the foods on your plate rank in terms of glycemic index. If you can influence the overall values in your meals to keep them moderate to low in terms of glycemic load (somewhat more practical than glycemic index in terms of overall diet) the health benefits go far beyond diabetes prevention, significantly impacting disease prevention as a whole.

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