What is the Glycemic Index?
Glycemic index (abbreviated to GI) is a way of classifying carbohydrate foods according to their effect on blood glucose. It is of special significance to people with diabetes, but there is also evidence that GI has health implications for people in general (so there are high and low GI but that doesn’t necessarily make them good or bad).
What does Low GI and High GI Mean?
When a food containing carbohydrate is eaten it is digested in the small intestine and sugars are released from the carbohydrate. Glucose is the major sugar, but other sugars are also released and then absorbed into the blood, along with the glucose. The body responds to the increase in blood glucose by releasing insulin—a hormone that (among other metabolic functions) causes the glucose to be stored for later use.
The glycemic index is a measure of how long it takes for the glucose from a food to be absorbed into the blood. The lower the GI, the slower and more even the rate of absorption of glucose into the blood. In essence, a food with a low GI means ‘slow release’ of carbohydrate into the body, while high GI means the carbohydrate is rapidly released.
If you prefer your information presented in video, you may find this clip useful.
Low GI foods (GI of 55 or less) include most mixed-grain breads, All Bran, legumes (peas, beans, soy products) and milk and yogurt. Foods which rank intermediate on the glycemic index (GI in the range 56-69) include Swiss formula muesli, white durum wheat spaghetti, Basmati, Arborio and long-grain rice and muesli bars. High GI foods (GI of 70 or more) include white and wholemeal bread, potatoes (boiled and baked), white Jasmine rice, some breakfast cereals (e.g., Cornflakes, Coco Pops) and sports drinks.
For a list of more than 60 common foods and where they sit on the glycemic index, you can read more here.
And if you are interested in other ways to control sugar spikes through diet, you might like to look at this.