What You Need to Know About the Glycemic Index

This index measures the speed at which a food elevates your blood sugar levels after its consumption. We're not talking about how much glucose it provides, but how fast it does so.
What You Need to Know About the Glycemic Index

Last update: 21 October, 2018

You may have never heard about the glycemic index. This indicator may interest you if you’re diabetic or need to control the amount of sugar you eat. If you want to know more about this index, keep on reading and we’ll tell you what it consists of, what’s it for and what its ranking is.

What is the glycemic index?

This index is a way to classify carbohydrates according to the way they affect the glucose levels in your body. It’s usually called GI. This scale goes from 0, the lowest level, to 100, the highest index value.

Girl eating pasta with a high glycemic index

The glycemic index of a certain food will depend on three different factors:

  • Cooking method. The more that a food is cooked, the higher its glycemic index value will be. We can find the lower index values on raw foods and the higher ones on grilled foods or foods that we process after cooking.
  • Food shape. If our cereals are whole or fragmented it’s a factor that drastically alters the glycemic index values. Whole cereals are harder to digest, which is why they release glucose into the blood stream slower than if we eat them in small pieces, such as with oats.
  • Fiber content. Depending on the amount of fiber in foods, we’ll absorb glucose at a higher or lower speed. The more fiber it contains, the slower our blood sugar levels will rise.

Depending on whether our blood sugar levels increase quickly or progressively, we can classify carbohydrates in the following ways:

  • Low. Foods with a glycemic index value under 55.
  • Medium. Foods with a glycemic index value between 55 and 69.
  • High. Foods with a glycemic index value between 10 and 100.

What is it for?

Knowing the glycemic index values of certain foods is important for consuming a balanced diet. There are times when we want a quick glucose release, and others when we need a prolonged release. Generally, we can say this index is something that interests mainly two groups of people: athletes and diabetics.

Glycemic index for athletes

Athletes should pay special attention to their diet and the glycemic index. They need to prepare their body for training sessions and competitions. It’s also important to eat correctly after working out, so that the body recovers from the physical effort they made.

Girl running by the beach
  • Before training. We recommend eating foods with a low or medium glycemic index. That way, you’ll get a slow glucose release over time.
  • During a competition. If it’s a competition in which you’ll have to put a lot of physical effort for long periods of time, the carbohydrates that you ate beforehand may not be enough. Carry some energy bars or special supplements to eat during the competition. That way, you’ll have an extra push whenever you need it.
  • After physical effort. It may seem that everything’s completed after the competition, but that’s not the case. You still have a very important task: recovery. Nourish your body with carbohydrates that have a high glycemic index value to replenish all of the nutrients that you lost during exercise.

Glycemic index for diabetics

Diabetic people should pay special attention to the glycemic index values in all of their foods. People who suffer from this disease have to deal with their pancreas not producing insulin, or not producing enough of it. Therefore, they must fulfill their lack of insulin with shots or pills.

Diabetics must eliminate products with a high glycemic index from their diets. Minutes after ingestion, they can cause a sudden rise in the glucose levels, and that can bring serious consequences to their health.

Some of these products are: white bread, honey, mashed potatoes, sugar or rice. That’s why in case they do eat it, they must do so in very small portions and only every once in a while.


This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.