The Importance of the Glycemic Index of Foods

The glycemic index of food is an interesting way to know whether or not it's a healthy option. Here we'll explain why, and how to use it in your favor.
The Importance of the Glycemic Index of Foods

Last update: 06 September, 2020

When it’s time to make a nutritional strategy for yourself, there are a lot of concepts out there that are extremely complex. The glycemic index of foods is one of the most important factors to take into consideration, but not everyone knows what it means. Here, we’ll teach you all about it!

Although people try to simplify their nutrition in terms of macronutrients such as carbs, protein, and fats, there are other components that aren’t considered. Many times, these other components can determine the success of a diet.

This is the case of the glycemic index. It’s not a macronutrient, but a biochemical measure that represents a very important concept in nutrition. It can even prevent illnesses.

Glycemic index: physiology of the absorption of hydrates

The glycemic index is a measure of the glycemic response in the body after ingesting food that contains carbohydrates. To really understand this phrase, it’s useful to clear up a few simple concepts about the way our bodies digest and absorb carbohydrates:

  1. First, we consume food. Differently than other macronutrients, carbs begin the digestion process while still in the mouth, thanks to certain enzymes called amylase present in saliva.
  2. The food passes through the esophagus to the stomach. This begins the most important phase of digestion. The carbohydrates are broken down into smaller molecules that are easier to absorb in the small intestine.
  3. Finally, the smallest molecules of glucose travel to the blood thanks to specific transporters in the intestines. The glucose in your blood needs insulin to penetrate the cells of the body. This means that when glucose enters the blood from the intestine, the body stimulates the secretion of insulin.

The glycemic index of foods is an indirect measure of the speed of digestion and absorption of its carbohydrate content. A high glycemic index indicates a higher spike of glucose in the blood after eating. It means that the food has been digested and absorbed rapidly.

High glycemic index sweets

High or low glycemic index: which is better?

As we’ve seen, food with a high glycemic index is rapidly digested and the glucose will pass to the bloodstream instantly. The presence of sugar spikes in the blood will stimulate the pancreas, which will secrete high quantities of insulin to help the body ingest the glucose into its cells.

We have to keep in mind that high levels of glucose in the blood over a long period of time can be toxic for the body. This is why the function of the pancreas in secreting insulin is so important.

Eating foods with a high glycemic index isn’t necessarily bad. However, a study published by the American Journal of Clinical Nutrition states that a diet based on these types of foods can put the pancreas in a situation of chronic stress. This can lead to illnesses such as diabetes or metabolic syndrome.

This is because the pancreas will, over time, become desensitized to the high levels of glucose and, in times of stress, won’t be able to sufficiently produce enough insulin.

Simple and complex carbohydrates

Surely all those who have read about nutrition have seen the concepts of simple and complex carbohydrates? The way that carbohydrates are classified is determined by their glycemic index.

  • Simple carbohydrates are digested and absorbed easily after being consumed. They create high levels of glucose and stimulate the excretion of high quantities of insulin. Some good examples of these types of foods are white bread and sugar.
  • Complex carbohydrates, on the other hand, are more difficult to digest. This is due to the fact that they’re usually composed of vegetables and it takes the body more time to break down the links between the distinct glucose. This is why they’re absorbed more slowly and they don’t cause blood sugar spikes. Good examples of these are whole-grain foods, legumes, and vegetables.

Plate of legumes

As we’ve seen, it’s more beneficial for your health to opt for foods with a lower glycemic index, which is present in complex carbs. Complex carbs take longer to digest and don’t generate blood sugar or insulin spikes. They also produce a better sensation of fullness. It’s a great tool to have if your goal is to reduce fat.

Eat more foods with a low glycemic index!

Reviewing the glycemic index of foods that you eat frequently can be really informative. If they have a high index, we recommend that you substitute them with other foods that have a lower index. In this way, you won’t only stay healthy, but you’ll also stay fuller for longer and be able to have a healthier body.

  • Sacks FM, Carey VJ, Anderson CAM, Miller ER, Copeland T, Charleston J, et al. Effects of high vs low glycemic index of dietary carbohydrate on cardiovascular disease risk factors and insulin sensitivity: The OmniCarb randomized clinical trial. JAMA – J Am Med Assoc [Internet]. 2014 Dec 17 [cited 2020 Jul 13];312(23):2531–41. Available from: /pmc/articles/PMC4370345/?report=abstract
  • Vega-López S, Venn BJ, Slavin JL. Relevance of the glycemic index and glycemic load for body weight, diabetes, and cardiovascular disease [Internet]. Vol. 10, Nutrients. MDPI AG; 2018 [cited 2020 Jul 13]. Available from: /pmc/articles/PMC6213615/?report=abstract
  • Bhupathiraju SN, Tobias DK, Malik VS, Pan A, Hruby A, Manson JE, et al. Glycemic index, glycemic load, and risk of type 2 diabetes: Results from 3 large US cohorts and an updated meta-analysis. Am J Clin Nutr [Internet]. 2014 Jul 1 [cited 2020 Jul 13];100(1):218–32. Available from: /pmc/articles/PMC4144100/?report=abstract