Dr Alan Barclay
Why you don’t need to keep count of the GI values of your meals and snacks
With the current trend to count each and every gram of carbohydrate (or every calorie/kilojoule) in a food or beverage, it is easy to understand that some people feel that they should be adding up the GI values of their meals or even keep count of the total GI value of all the meals and snacks they have in a day.
Relax. You absolutely don’t need a calculator nor a pen a paper when you eat the low GI way. It’s not necessary, nor is it a good idea for a number of reasons.
Firstly, unlike grams of carbohydrate and other nutrients or calorie (kilojoule) counts, the GI is a measure of quality – not quantity. A useful analogy is that of mixing paints – the final colour will reflect the dominant colour used, not simply the sum of its parts.
It’s true that researchers sometimes calculate what is called the average dietary GI, or to be more precise, the weighted average GI – where the weighting is a percentage value representing the proportion of total carbohydrate contributed by each individual food and beverage. But this is for studies to be published in peer-reviewed scientific journals. For everyday use, this is simply not necessary as we know from what’s called ‘dietary modelling’ that simply replacing most of the high GI carbs you eat with with medium or low GI ones will lower the GI of the average person’s diet sufficiently to reduce their risk of developing type 2 diabetes and will also help them achieve and maintain a healthier weight.
In addition, numerous studies have shown that people with diabetes can improve their glycated hemoglobin (a measure of their average blood glucose level over a 3–4 month period) simply by lowering the GI of their diet. In these studies, the people did not have to calculate their daily GI values– it was not necessary: they just used the substitution model (look how easy it is):
Secondly, we also know that you don’t have to sweat over making sure every meal you eat is low GI. This is due to what’s known as the second meal effect: if you eat a low GI meal, you reduce the glycemic impact of the carbohydrates eaten at the following meal. Research has found this applies to a high GI breakfast eaten after a low GI dinner the night before, or a high GI lunch, after tucking into a low GI breakfast.
Finally, like grams of carbohydrate and other nutrients and calories/kilojoules, GI values aren’t 100% accurate – for all of the same reasons: foods are grown in different soils, under different weather conditions, and consequently, all have a slightly different nutrient composition – so it is pointless to try and be too precise with GI (or any other nutrient) values.
So ‘don’t sweat the small stuff’ and add stress to your life. Simply swap the high GI carbs you eat at most meals for low or moderate GI counterparts and you will achieve a low(or lower) GI diet overall. And don’t forget about the total calories/kilojoules, type of fat and sodium content of your meals – GI is only one part of healthy eating.
For more information on GI values and why you don't need to keep count, please feel free to contact me: firstname.lastname@example.org
For more information about the GI Symbol Program
Dr Alan W Barclay, PhD
Chief Scientific Officer
Glycemic Index Foundation (Ltd)
Phone: +61 (0)2 9785 1037
Mob: +61 (0)416 111 046
Fax: +61 (0)2 9785 1037