What exactly is the Glycemic Index? DR RAJEN M. gives a definition that is easy to follow as he talks about its effectiveness in helping identify food with the effect on blood sugar.

ALL carbohydrates become sugar. It is just a matter of how fast the change takes place. Some become sugar very quickly. Others are slow to digest. They push up blood sugar slowly.

Sugar is a good source of energy. However, it has a huge drawback. In high doses, it is toxic. That is why your body will never store excess sugar.



Your body performs best when your blood sugar is kept relatively constant. If your blood sugar drops too low, you become lethargic and hungry. This condition is called hypoglycemia.

If your blood sugar goes too high, there is tissue damage. This is a crisis situation as prolonged tissue damage causes death. You secrete more insulin. Insulin lowers blood sugar. It converts excess sugar to stored fat.


• Roller Coaster Effect

A fast rise in blood sugar forces your body to produce a large amount of insulin. Thus, when you eat foods that cause a large and rapid rise in sugar, you may feel an initial elevation in energy and mood as your blood sugar rises.

However, this is followed by a cycle of increased fat storage, lethargy, and more hunger. Remember, how you last felt after a heavy banana leaf lunch?

Although increased fat storage may sound bad enough, individuals with diabetes (diabetes mellitus, types 1 and 2) have an even worse problem. They are unable to secrete or process insulin causes their blood sugar to rise too high, leading to a host of additional medical problems.


• Atkins Diet

This is why diets propounded by Dr Robert Atkins, which were very low carbohydrates, were so popular.

By cutting out all carbohydrates which eventually become sugar, you dramatically drop the levels of your circulating blood sugar. Hence, blood sugar comes down as does stored body fat.

However, many find a low or, worse still, no carbohydrate diet difficult to stomach. They may be delighted to know that there is a way to rank carbohydrates by way of an increasingly internationally accepted Gylcemic Index.

The theory behind the Glycemic Index is simply to minimise insulin-related problems by identifying and avoiding foods that have the greatest effect on your blood sugar.

The Glycemic Index is a numerical index that ranks carbohydrates based on their rate of glycemic response (i.e. their conversion to glucose within the human body).

Glycemic Index uses a scale of 0 to 100, with higher values given to foods that cause the most rapid rise in blood sugar. Pure glucose serves as a reference point, and is given a Glycemic Index (GI) of 100.

Glycemic Index values are determined experimentally by feeding human test subjects a fixed portion of the food (after an overnight fast), and subsequently extracting and measuring samples of their blood at specific intervals of time.

The earliest known work on the Glycemic Index was done by Dr David Jenkins and associates at St Michael’s Hospital in Toronto.

More recently, an effort to expand the Glycemic Index has been made by Jennie Brand-Miller and her associates at the Human Nutrition Unit of the University of Sydney in Sydney.


• Glycemic Load

The Glycemic Index compares the potential of foods containing the same amount of carbohydrate to raise blood glucose. However, the amount of carbohydrate consumed also affects blood glucose levels and insulin responses.

The glycemic load of a food is calculated by multiplying the Glycemic Index by the amount of carbohydrate in grams provided by a food and dividing the total by 100.

In essence, each unit of the glycemic load represents the equivalent blood glucose-raising effect of 1 gram of pure glucose or white bread.

In other words, the Glycemic Index talks about the quality and type of the carbohydrate.

The glycemic load, on the other hand, talks about the quantity of the carbohydrate available in a food.

Water melon, for example, is a food rated high in the Glycemic Index as it is high in fibre content and digests fast.

However, the amount of sugar available is low. In other words, it has a low glycemic load. That makes it a relatively good carbohydrate, even on a low carbohydrate programme.


• Lowering Dietary Glycemic Load

Some strategies for lowering dietary glycemic load include:


• Increasing the consumption of fruits, vegetables, legumes (peas and beans), nuts, and whole grains


• Decreasing the consumption of starchy high-glycemic index foods like potatoes, white rice, and white bread


•Decreasing the consumption of sugary foods like cookies, cakes, candy, and soft-drinks.