Glycaemic index or GI is a measure of how rapidly blood-glucose levels increase after eating certain carbohydrate based foods. The majority of foods are classified into 3 groups, low (under 55), medium (55-69) and high (greater than 70). The GI value is determined by various factors including the type of carbohydrates, how has it been processed and the presence of fat or fibre. In general low GI foods tend to contain more fibre and are less processed in comparison to high GI foods, however there are always a few exceptions to the rule (i.e.: chocolate is low GI but high in fat and highly processed).
High GI foods release glucose quickly, causing a rapid rise in blood glucose levels. This leads to an increased release of insulin to help drop these glucose levels back down which in turn leads to an increase in fat storage. Low GI foods in contrast release glucose into the bloodstream steadily over a few hours; this limits the spikes in blood glucose levels therefore requiring less insulin to help balance out the levels.
GI diets are recommended for people with diabetes, insulin resistance, cardiovascular disease, certain digestive disorders and weight loss. Low GI carbohydrates help to improve diabetes control, reduce the risk of heart disease, cholesterol, help you feel fuller for longer (controlling hunger) and prolong your exercise duration. A benefit of high GI foods is to rapidly refuel carbohydrate stores after exercise or a sporting event.
Most low GI diets recommend that you consume large quantities of fibre-rich vegetables and legumes, fresh fruit, wholegrain breads/cereals with low GI values, limit saturated fat intake. GI diets also include food combining, where lean proteins are consumed to further lower the GI value of the meal. Low GI diets are a way to help your body to work at its optimal level via nutrition and help you to lose/maintain weight and teach you principles to eat better and feel good about yourself.
You can obtain a list of GI foods and their values in many nutrition books or at the following website www.glycemicindex.com . These values can help you to determine appropriate meals with low GI values. So next time you’re out shopping, think about what you’re buying and if it’s a low GI food choice and become more informed about what you’re eating.