GI - what is it and what does it mean?

By Morgan Higgins APD

​How many times have you walked down the supermarket aisle or seen an ad on tv where they rave about GI this and low GI that? But what does it all mean, why is it an advertising point and how does it fit into our everyday diet?
 
GI stands for Glycemic Index. It is a score given to a food which identifies the speed at which the carbohydrates are broken down, digested, and absorbed into the bloodstream. So in other words it is a good way of describing how long a food will provide your body with energy.
 
If a food has a high GI it means that it will be broken down and digested very quickly in the body and cause a quick release of glucose into the bloodstream. This will cause a rapid increase in your blood sugar levels.  A food with a low GI score will be absorbed much slower within the body. The GI of a food is rated on a scale beginning at 0 with foods with a low GI being under 55 foods between a 55 and 100 with a high GI.
 
But what does this mean for energy levels? Well a food with a high GI will cause a quick spike in your blood sugar levels and energy, and subsequently a fast drop and energy dip. A low GI food however will result in a steady balanced rise in blood sugar levels and provide longer sustained energy, it will also help you to feel fuller for longer and curb cravings to overeat.
 
So which foods have a High GI? well there are many foods which will cause a quick rise in blood glucose levels. Some High GI common household foods include white bread, most white rice, potato, all cereals which are not ‘low GI’ certified, cracker biscuits, lollies, honey, corn syrups and alcohol.
 
Low GI foods have been shown to improve glucose levels particularly in individuals with diabetes, due to their slow release action. According the World Health Organisation and Food and Agriculture Organisation recommendations for healthy eating and disease prevention, diets based around low GI foods will assist in preventing common affluent diseases such as diabetes, cardiovascular disease and obesity. Low GI foods include grain and seeded breads, traditional oats and muesli, most vegetables (excluding white potatoes, corn and peas), brown rice, wholemeal pasta, quinoa, soba noodles and reduced fat dairy. 
 
In Australia we are lucky enough to have a foundation which regulates the nutrition claims and criteria of supermarket food choices. By using the Low GI symbol shoppers are easily able to identify products on the shelf which definitely have a glycemic index below 55. Looking for this symbol when you are shopping will make this healthy choice much easier.
 
What affects the GI of a food? There are many things that affect the GI of a food. Fats and protein will slow down the digestion of carbohydrates in the body, meaning that foods with high fat and protein amounts will be considered lower GI.
 
Highly processed foods require less digestion and therefore have a Higher GI score, unprocessed oats will be low GI compared to quick 1-minute oats.
 
The cooking process of a food will affect its GI as overcooking will soften foods and speed up digestion. Al dente pasta for example will have a low GI whereas over-cooked pasta will have a much higher GI.
 
Some easy hints to increase your consumption of low GI foods include:

• choose high fibre breakfast cereals over processed refined cereals
• choose wholegrain snacks and crackers over processed chips and snacks
• include more than 5 serves of fruits and vegetables everyday
• swap regular white potatoes for a low GI variety or sweet potatoes and pumpkins
• eat less refined, processed and easy convenience foods.

 
When it comes to a healthy well balanced diet look for the low GI symbol at the grocery store. Choosing low GI carbohydrates is definitely the best option for balance and healthy weight loss. They will provide your body with slow release energy, will prevent a quick spike in your blood sugar levels and may help reduce the risk of obesity, cardiovascular complications and type 2 diabetes.
 
So next time you go to the supermarket you can look at the Low GI claim and know that you are making a healthy choice.