How Is Glycemic Index Determined?

The Glycemic Index of a food is calculated by measuring the two hour blood glucose response curve or AUC following the intake of a fixed portion of carbohydrate (generally 50gm.) In order to calculate the GI of a food, the AUC of the test food is divided by the AUC of the standard blood glucose level and multiplied by 100.

The average GI of a food is calculated from the results obtained from 10 human subjects. The standard and the test food must contain equal amount of available carbohydrates. The average GI obtained gives a ranking of the food.

In the present system of accessing the Glycemic Index of a food, the GI value of glucose is 100. Glucose is accepted as the reference food for the calculation of GI as it is the most abundant carbohydrate in the world. It generally gives a standard value, when tested in the labs.

Using GI in Deciding What to Eat & Fat Burning

Knowing the GI of a particular food is important to make proper choices about what food to eat and when. A high GI food is helpful for immediate recovery of energy after high endurance exercises. A food with low GI is suitable for normal diet, as these will release glucose and energy slowly and steadily into the body.

The glycemic effects of various types of food are dependent on various factors. The most important factor is the type of starch that the food substance contains. It can be amylopectin or amylose. The fat and protein content of the food also determines the glycemic effect the food will produce. The other important factor is the presence of other organic salts and acids in the meal.

For example, the presence of vinegar in the meal will lower the GI of any food substance. The presence of fat and other soluble dietary fibers affects the GI value of any food substance. Both the fats and fibers slow down the rate of digestion in turn reducing the GI value of the food.

A recent study revealed consuming alcohol just before a meal actually reduces the GI of the food substances by as much as 15%. The study also concluded that it is better to consume alcohol after having a meal, rather than before.

Since you now know the impact of insulin on weight loss, fat burning and overall health you can understand the importance of knowing the GI of foods.  Making food choices with the GI in mind is a very potent way to avoid obesity, lead a healthy life, and be energized. By making more educated decisions on what you eat, this will help you with fat burning.