What is the glycemic index( GI)? Why is it important to us? and why we should know how to calculate it. There are these problems when you read this title. I described in my previous article, “Which rice has the lowest glycemic index?” the types of lowest GI rice. Moreover, how essential they are for our health. Hopefully, I’ll be able to explain all your doubts in this article too.

What is Glycemic Index?

The glycemic index (GI) refers to a system that classifies carbohydrate-containing foods based on their effect on blood sugar level elevation when consumed alone. It determines how fast each food elevates the level of your blood glucose. By categorizing foods into three types by categorizing them according to their GI value, we can organize them accordingly. Foods with a high GI value have a GI value between 70-100. Low-GI foods have a value below 55 and are regarded as preferable whenever feasible.

High GI food

Foods with a high glycemic index (GI) elevate quickly in blood sugar levels. These kinds of carbohydrate-rich foods are rapidly digested by the body which causes a speedy rise in blood glucose levels. While high-GI foods can be beneficial to athletes or those who need immediate sources of energy, it’s vital to understand the overall effects on our bodies from such foods and adopt suitable strategies for ingestion.

Medium GI food

Being aware of foods with a moderate or medium-level glycemic index (GI) makes meal planning simpler by providing readily available healthier options that help prevent sudden spikes in blood sugar levels. Whole grains like oats, quinoa, barley, bulgur wheat, as well as brown rice contain moderate amounts of carbohydrates while giving valuable fiber as well as proteins hence there is usually little fat content found in them. Additionally, starchy vegetables such as sweet potatoes, yams much more pumpkin offer substantial nutritional values while having a moderate ranking ranging from 50 to 69 scale of 100.

Low GI food

0-55 A low glycemic index (GI) diet is a dietary approach wherein emphasis is placed on the intake of foods with a low GI rating. The main intention of this diet is to assist individuals in maintaining stable blood sugar levels and minimizing the risk of conditions like diabetes, and heart disease among other ailments.

Low GI foods comprise whole grains, legumes fruits, vegetables, and dairy products including milk as well as yogurt. These foods usually contain higher concentrations of fiber or fat thus slowing down digestion rate hence absorbed slowly contrasted to high-GI items like white breads or sweet tasty snacks. Through such low GI foods, people are able to promote better blood sugar control thus supporting general health and wellness status.

Calculating the GI

Calculating the Glycemic Index (GI) of a meal is merely finding out the effect this meal has on blood sugar levels as compared to a ‘reference food’ (usually glucose or white bread with a GI value of 100). The GI value of a meal shall be expressed in percentage relative to the reference food. Here is an example calculation:

Step 1:

Select foods in the meal: Now, for this particular example, let us say the meal consists of 50 grams of cooked brown rice and 200 grams of boiled sweet potatoes.

Step 2:

Obtain the GI values: Next, you will have to find out the GI values of the individual foods. You can refer to a good glycemic index database like the International Tables of Glycemic Index or consult a GI chart. For our present illustration, let us assume that both the foods – brown rice and sweet potatoes – have a GI value of 50.

Step 3:

Calculate the proportion of each food: Based on the total weight here 250 grams, calculate the proportion of each food in the meal. So, the proportion of brown rice in the meal shall be 0.2 (as per the above formulation); while the proportion of sweet potatoes shall be 200 grams / 250 = 0.8 (relative to the entire meal).

Step 4:

Calculate the weighted average: Multiply the proportion of each food by its respective GI value and sum up the results. In this case: (0.2 * 50) + (0.8 * 70) = 10+ 56=66

Step 5:

Divide by total proportion: Divide 66 by the total proportion of the whole meal. Here By 66/1=66

Step 6:

Interpreting result: The resulting GI value 66 explains that this meal is considered to have a moderate glycemic index.

Leave nothing out here; everything is important, especially from steps 2 and 3. You should get it straight especially since the source and preparation of the food may differ.

If you need the glycemic index of any food, you can go to this site (GI Search – Glycemic Index) and search for it.

References

• Calculating meal glycemic index by using measured and published food values compared with directly measured meal glycemic index | The American Journal of Clinical Nutrition | Oxford Academic (oup.com)
• What is the glycaemic index (GI)? – NHS (www.nhs.uk)

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