Definition of The Glycemic Index!

Are you wondering what the definition of the glycemic index is? You have come to the right place!

Chances are, you have heard all kinds of mixed opinions on the glycemic index.

Well, I don’t portray opinions as facts in any of my articles.

I portray facts as facts.

If you currently believe the glycemic index is the supreme ruler of the quality of a carbohydrate, you have been informed wrong.

What Is The Glycemic Index?

The glycemic index is a scale that ranges from 0 to 100 and it measures how quickly a carbohydrate gets into the bloodstream as sugar (glucose). This also gives us a rough idea of the insulin response that will occur.

The glycemic index of a food is measured by providing individuals with 50 grams of available carbs for that food (total carb content minus the fiber content) and measuring their blood glucose levels every 15 to 30 minutes. This information is plotted on a chart to see how the blood glucose levels change over time for different carbohydrate sources.

It also shows how much of an insulin increase we can expect to see. The more drastic and high the blood sugar spike, the greater the insulin spike we will see.The more controlled and lower the blood glucose increase, the lower the insulin increase will be.

This is because insulin regulates blood sugar levels by transporting glucose into muscle and fat tissue (primarily).

The more glucose that gets into our bloodstream and the quicker that happens, the more insulin and the quicker it needs to be released for blood sugar regulation.

What Use Does The Glycemic Index Provide?

Fat Loss:

Unlike many “experts” or “gurus” lead you to believe, having a high glycemic food does not cause you to gain fat long term. Yes, a high glycemic food will cause an insulin spike, which will cause more fat storage, but this is in the short term. Insulin doesn’t stay permanently spiked.

Those higher glycemic foods can only cause so much short term fat gain. 100 grams of high glycemic carbs taken in one dose will cause a high insulin spike, but the same fat storage effects will be expressed from 100 grams of low glycemic carbs because the insulin increase will last longer.

If you are in a calorie deficit, your body will need more energy than you are giving it, which will result in it needing to pull energy from fat stores. A calorie deficit will cause your body to need more adipose tissue (fat) energy than you stored from nutrition that day.

I am not saying high glycemic foods are the same as low glycemic. The problem with primarilyeating high glycemic foods is they tend to be less filling and obtain less nutritional value. So if high glycemic foods allow you to easily overeat and be in a calorie surplus, then they lead to fat gain. However, this fat gain does not come from the high glycemic index. It comes from the excess of calories from overeating these foods.

So the actual glycemic index of a food is relatively insignificant for fat loss. It is more about the calorie content and nutritional profile of a food, which does not require the glycemic index to determine.


The glycemic index can be beneficial for determining which foods will be really good to eat prior to and after exercise.

This is because exercise requires energy. If we want to perform optimally, we need to have available energy. The most efficient nutrition that our body uses for energy is glucose. Carbs break down into glucose. So if we eat a high glycemic carbohydrate 30 minutes to an hour prior to training, those carbohydrates will be readily available for us to use for fuel.

Assuming our workout isn’t 2+ hours long, we likely won’t experience much of a crash either if we get in good post-workout nutrition!

Another great method is eating lower glycemic carb sources one to two hours prior to training. These won’t break down as quickly so they will still be ready to be used as fuel for your training session.

This can be really good because we will likely be eating more nutrient-dense carb sources in lower glycemic foods. This is an added bonus if you have the goal of fat loss since lower-calorie and more filling options aid in making the fat loss process as smooth as possible!

With that being said, this doesn’t mean you can’t have higher glycemic carbs 1 to 2 hours before training if that is what you prefer and or is right for your goals. Even if you had white bread 2 hours before training, the breakdown of those carbohydrates can be slowed down with the presence of other nutrients.

Fibre, protein, and fats are all really good at slowing down the breakdown of nutrients. So if a high glycemic carbohydrate is eaten with a fair amount of some, or all of those listed nutrients, it will break down slower and you have yourself an awesome 1 to 2-hour pre-training meal or snack!


Other uses of the glycemic index may include finding foods that work well for diabetics. Diabetics have a tough time or in some cases can not produce their own insulin, so they need to limit high glycemic foods that cause large spikes in blood sugar because they do not have the means of properly regulating that blood sugar.

Having consistently higher blood sugar may lead to certain health complications.

I am not a doctor and do not know all the specifics of practical uses of the glycemic index for medical conditions. This is just an example to show that there are important uses of the glycemic index. This is not medical advice. Speak with a doctor for information.

That’s All!

That is what the glycemic index is, how it works and how it is typically used, and how it should/can be used! Do you have questions or comments? There is a comment section just for that! Leave them there and I will be sure to respond!


Here are some other articles that may be beneficial for your knowledge!

Guidelines of Fat Loss

Weight Loss and Nutrition Myths

What is a Caloric Deficit?


Until Next Time,

Kohl Johnson

Please refer to my liability disclaimer to ensure you know who is responsible for the use of this information after reading.






Support is much appreciated if you benefited from this:

Kohl Johnson

I am a 16-year-old fitness fanatic! I have learned nothing but quality training and nutrition information from the utmost well-respected individuals in the field. Now, my only focus is to share this knowledge with you for your benefit, in the most honest way possible. We are all in this together! LET'S GO!

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