Does dieting, weight loss, weight control or balanced nutrition fall into your healthcare regime? Then you've probably heard of ‘Glycaemic Index’ or ‘Low GI Diets’, but might not know exactly what it is or how it works?
Carbohydrates are used by the body for energy, they are broken down by the digestive system and converted to sugar. The sugar enters the blood stream and is transported around the body to be absorbed and utilised accordingly.
Firstly, not all carbohydrate foods are created equal, in fact they behave quite differently in our bodies. Some Carbohydrates break down and enter the blood stream quickly, while others break down and enter the blood stream slowly. Glycaemic Index (GI) is a rating used to indicate which of these two categories a certain food falls into.
The GI of a specific food is determined by comparing the blood glucose response of a specific food with the blood glucose response of glucose. Glucose is absorbed quickly from the small intestine and generally causes the greatest and most rapid rise in blood sugar levels.
High GI
High GI foods are normally quite refined, because of this, they are broken down very quickly by the body and cause a rapid spike in blood glucose levels, these levels cannot be sustained and invariably drop just as rapidly.
Major fluctuations in blood glucose levels, causes a lot of stress on the body and long term effects could include, diabetes, circulatory problems, heart disease, digestive problems and chronic fatigue.
High GI carbohydrates
- Biscuits and crackers
- White bread
- Potatoes
- White rice
- Instant noodles
Low GI
Low GI foods normally contain more fibre and are wholegrain, therefore they are broken down more slowly and cause a gradual rise in blood sugar levels. Sustained glucose levels will ensure better energy levels throughout the day, a healthier body and digestive system.
Low GI carbohydrates
- Non starchy vegetables
- Pulses
- Sweet potatoes
- Baby potatoes
- Pasta
- Brown rice
What is Glycaemic Load (GL)
The Glycaemic Load (GL) works in conjunction with Glycaemic Index - it is an expression of how much impact or influence the food will have on the blood glucose levels, based on a specific portion size or concentration.
In laymen’s terms, a larger amount of a food with a medium GI and contains few available carbohydrates would have the same effect on blood sugar as a smaller amount of a food that has the same GI but a higher carbohydrate content.
Here’s the formula for calculating Glycaemic Load: Multiply the GI value of a food by the amount of carbohydrate per serving and divide the result by 100. You can then measure the Glycaemic Load accordingly
- 20 or more is high
- 11-19 medium
- 10 or less is low
A food product with a low GI and low GL is obviously the best choice to make. The aim is to keep the total GL per day under 100
Who can benefit from a low GI Diet?
Simply, everybody. When you make use of the Glycaemic Index to prepare healthy meals, it helps to keep your blood glucose levels under control. Whether you are an athlete or a couch potato, everybody stands to benefit from knowing about this relatively new concept in good nutrition.
How to Switch to a Low GI Diet
The basic technique for eating the low GI way is simply a "this for that" approach - by swapping high GI carbohydrates for low GI carbohydrates. You don't need to count numbers or do any sort of mental calculations to make sure you are eating a healthy, low GI diet.
- Choose breakfast cereals based on wholegrain oats, barley and bran.
- Use breads that are wholewheat or specifically labeled Low GI
- Reduce the amount of potatoes you eat, opt for baby potatoes or sweet potatoes, they have a lower GI rating
- Eat controlled portions of fruit and starchy vegetables (about as much as you can fit into a closed cupped hand, per portion), although these foods are healthy and full of fibre, too much can lead to high glucose readings
- Reduce fruit juice intake by diluting fruit juice with large quantities of water or choose a fruit juice that ranks well on the GI table
- Use Basmati or brown rice instead of Jasmine or white rice
- Enjoy pasta, but stay away from rice noodles or instant noodles
- Eat plenty of fresh salad vegetables
As a consumer of food products, you need to be informed of the qualities of the food you eat and how it may affect your blood glucose levels, by familiarising yourself with nutritional labels of a product. You can also look for the following symbols on your food items, which will guarantee that the product conforms with the South African GI and GL standards.
For more information on food classifications, there is a book on the market called the “South African Glycemic index and load guide”, which lists South African food products, by brand, commonly available in our grocery stores. Each product contains a GI and GL reading. You can also go to the Glycaemic Index Foundation for more information about purchasing the book and the research behind GI Nutrition.
