Glycemic Index (GI)

GLYCEMIC INDEX (GI) is a scale which helps to rank carbohydrate- rich foods, depending on how they affect blood glucose levels, by comparing them to glucose. In simple terms, GI measures how much your blood sugar level increases in a span of 2 - 3 hours after having food.

The scoring is between 0 to 100 with glucose being the reference food with a GI value   fixed at 100.  It is a new system of classifying carbohydrate containing foods, according to how quickly they raise blood glucose levels in the body.

The term ‘GLYCEMIC INDEX’ (GI) was first invented by David Jenkins & Thomas Wolever at St. Michael hospital in Toronto, Canada in 1981. Since then, it has been a subject of debate. More recently, an effort to expand GI has been made by Jennie Brand-miller & her associates in Sydney, Australia.

To better comprehend GI index, we need to understand that all carbohydrates, from starches to plain sugar (commonly called as “Table sugar”), share a basic biological property i.e. they can be digested and converted to glucose in our body.  The common misconception among the general public is that by avoiding  ‘plain sugar’ they can avoid diabetes and take care of their ‘sugar’ level in the blood.   I do not eat any ‘Mitha’ (‘Mitha’ means sugar in Hindi); is a common reply from the patients when they are asked to avoid sugar.  

When a doctor or dietician refers to ‘sugar’ in the food, they mean Carbohydrates and the patient understands it as table sugar. 

GI is possibly one of the scientific ways of looking at carbohydrate- rich food and finding out which item when consumed is likely to increase the level of glucose in the blood.

Carbohydrates with high GI causes a rapid increase of blood sugar, whereas diet based on low GI are low in sugar but high in fiber. They cause a slow rise of blood sugar and are, therefore, ideally suited for diabetic patients. 

Here’s a quick overview of what’s high and what low In GI is

Classification	GI Range	Examples
Low GI	55 or less	Most fruits and vegetables (except potatoes, watermelon), grainy bread, brown rice, fish, egg
Medium GI	56-69	Whole wheat products, basmati rice, sweet potato, table sugar, white rices
High GI	70 or more	Flakes, rice krispies, baked potatoes, white bread, straight glucose (100)