GI is a term that is being thrown around a lot lately – especially a low GI diet. But what exactly is Low GI and why is it so good for us?
GI stands for the “Glycaemic Index”, and it is a ranking from 1 to 100 that measures the effect of a food on your blood glucose levels over the two hours after the food is eaten. A low GI food is 55 or less, a medium GI food is 56-69, and a high GI food is 70 or more. A higher GI food will see the blood glucose level rise and fall sharply, while a lower GI food will see a slower, steadier rise in blood glucose levels.
Very high glucose levels after a meal is damaging to the arteries and other blood vessels and they cause an excess of insulin in the body. Eating low GI foods means that you can avoid these dramatic rises and falls in blood glucose levels, therefore giving you a steadier stream of energy. You will reduce your cravings for sugar and other sweet foods. Your risk of heart disease and other chronic diseases is also reduced. Low GI foods are excellent for weight loss. Not only do they fill you up and keep you feeling satisfied for longer, thus helping you to reduce your daily kilojoule intake, they also reduce insulin levels and help you to burn more body fat and less muscle, so that your metabolic rate is higher.
A low GI diet is not simply a “diet” – it is in fact a healthy eating plan. Research has shown that a high GI diet increases the risk of type 2 diabetes, heart disease, stroke, gall disease, certain cancers, and even eye disease. Some of these are referred to as “lifestyle diseases”. It is not the fact that people are eating too many carbohydrates in their diet, it is that they’re eating too many of the wrong kind of carbohydrates. By following the low GI diet, you are eating more of the right carbohydrates, and thus reducing the risk of the aforementioned diseases. Currently, the average GI of the Australian diet is 57. To reduce the risk of common lifestyle diseases, it should be reduced by 10 to 15 units (to 42-47).
Because it is about switching to the right kind of carbohydrate, the low GI eating plan is one that can be followed over a long period of time with no ill effects. In fact, it has the ability to make you feel better for longer.
There is no need to know the GI value of every food. Fruits and vegetables (except potatoes), should be eaten daily regardless of their GI levels. It is adequate to know the GI levels of the major carbohydrates in your diet – cereals, breads, pasta, rice, etc – and to choose the ones that are low GI. This will give you the healthy benefits of low GI eating.
Be aware that the GI of your food should not be the sole determining factor in your choosing to eat it. For example, chocolate is low GI, but is bad for you if you have too much. First look at the saturated fats in the food, and look at how many nutrients it contains, and then apply the GI.