The Glycemic Index – Description And Use

The glycemic index is a method created to specifically classify foods based on the effect they have on blood glucose. It is  an attempt to measure how a certain food affects the sugar levels present in a person’s blood system.

When a person ingests food and it passes through their intestines, the blood sugar values ​​change. This change depends on the nutritional value of the food eaten. For example, the blood glucose of a person who eats sweets will not be the same as that of a person who eats noodles.

The glycemic index tries to reflect the ability of foods to increase blood sugar. It is not just a number in itself, but a mathematical formula developed for this purpose.

According to this system, there are basically two types of foods:

• Low glycemic index in foods:  The form that does not increase blood sugar levels very much after ingestion. In addition, the increase they produce lasts longer.
• High glycemic index in foods:  Likewise, these types of foods lead to an instantaneous high blood glucose level in the body, but it does not last very long.

The formula was developed in 1981 and the finished tables in 1995. These have more than 500 types of foods classified according to their glycemic index. There is also the international table since 2002, developed by the researcher, Foster, and his team. It is currently the most recognized of them.

Factors affecting the glycemic index

You will need to understand that the glycemic index is not equal to the number of carbohydrates present in foods. The effect it causes on blood sugar is one thing, and its nutritional composition is another (this confusion often turns out to be counterproductive).

The official classification takes place in three groups and the value of the glycemic index is given by:

1. The type of simple sugar of which it is composed

As we mentioned above, the nutritional composition is not directly equal to the effect on blood glucose. Potatoes, for example, contain a type of simple sugar that is different from that in milk. Thus, the body will react differently and process them at different speeds, after consuming these types of foods.

2. The presence of other nutrients

Sugar is not isolated in foods, but is there in conjunction with other substances, such as fat. The sugar from nuts, for example, is there along with fat and dietary fiber. So the body takes longer to separate that sugar and digest it.

3. Type of processing

Cooked, grilled or fried foods do not have the same effect on blood glucose. If they have been stored in a refrigerator or in a freezer, their final effect will also be different. For example, we know that mashed potatoes have a higher glycemic index than a fried potato.

Fruit juice also has a higher glycemic index than a whole piece of fruit. And pasta al dente has a lower index than when cooked for too long.

Values ​​used in the glycemic index

The numbers in the glycemic index come from laboratory tests and formulas. For use in our everyday lives, it is not necessary to be able to understand how to perform the calculations or how the scientists came up with these formulas.

However, we can say that it is a proportional measure of the rate at which carbohydrates in foods manifest themselves in the form of blood sugar. Thus, it is proportional because the reference value is always the same as with pure glucose.

Pure glucose has a value of 100 and based on this reference, we can establish the indices for the rest of the types of foods and form three general groups:

• Low glycemic index:  This is a food with a value between 1 and 55.
• Medium glycemic index:  These foods have values ​​between 56 and 69.
• High glycemic index:  This applies to all foods with a value higher than 70.

The higher the glycemic index, the faster the blood glucose will rise after ingestion. In contrast, there is a lower glycemic index for foods that do not increase blood glucose significantly after consuming it.

Let us emphasize again that this value does not reflect the nutritional composition of a particular type of food. It does not give us information about fats in foods nor kilocalories. Primarily, it tells the specific amount of sugar it contains.

How does the glycemic index affect everyday life?

As we said before, the measurements we are talking about are not the only ones we need to be aware of. It is a measure that can help you plan a diet for diabetics, but always in combination with other factors.

One value that helps compliment this is the  glycemic load  that measures the quantity and quality of carbohydrates in a serving of food. For example, a musli bar has a high glycemic index but a low glycemic load. This is because the portions are always small.

Additionally, food varies when it comes to diet plans developed by professionals. The glycemic index in these cases increases from the combination. For example,  one can compensate for a serving of high value food if one eats the same dish along with another with low index.

Likewise, there are several meals in a day so that their individual glycemic index is combined. We know that a meal with a low index is able to improve the glucose assimilation for the next meal, as a cumulative effect.

Of course, in the presence of metabolic diseases such as diabetes, it is always fundamental to get guidance from a nutritionist when it comes to one’s diet. You can get answers to many of your questions about your diet if you talk to this type of professional.