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Ketogenic Diet: What it is & How it Works

  • DATE: MAY 11, 2020


Throughout the years, many different kinds of diets have raised their popularity by promising fast and long term weight loss results, without a yo-yo effect: Atkins diet, 90-day diet, vegan and vegetarian diets, whole 30 diet, etc.

Currently, a new “star” has risen on the weight-loss horizon: the Ketogenic diet. Many people have already seen promising results, while others criticize it. Regardless of the apparent weight loss that occurs on this diet, the science behind this diet and its long term effects is still unclear.

This article will guide you through the processes that happen in your body when you “go keto.”

  1. What is keto “diet”?

  2. How does the keto “diet” work?

    1. What is Ketogenesis and when and why does it occur?

    2. What happens during gluconeogenesis?

  3. Conclusion

What is keto “diet”?

The ketogenic (or simply “keto”) “diet” is an eating regime that was developed in the past to cure epilepsy, control diabetes, and high blood sugar. [1]

Nowadays, it is widely used not only for weight loss, but also for controlling insulin resistance for people with pre-diabetes and seizures. New evidence is pointing towards the potential health benefits of using the ketogenic diet as a protective measure for the nervous system and cognitive decline, although more studies are needed in order to determine the effect of this diet on these disease states. [2]

For the ones who aim to adopt the keto regime, it’s crucial to count the intake of carbohydrates, proteins, and fats. The regime focuses on low-carb, moderate-protein, and high-fat foods.

The carbohydrates consumed by a person on a ketogenic diet should be about 5-10% of his/her total calorie intake, while the proteins should account for 20-25%, and the fats: 70-75%. [3] In other words, the keto “diet” promises you tolose weight while eating fatty foods.

If anyone had said that at the time when the Atkins diet was popular, everybody would have laughed very hard. Anyways, now let’s see how the ketogenic process works.

How does the keto “diet” work?

*Before explaining anything else we remind you that all the carbohydrates break down to sugar (glucose) molecules when metabolized.*

The recommended daily intake of sugar for adults is about 30 grams. [4]

But what happens when your glucose intake is way lower? Does your body start suffering? The common answer is: “Not really.”

The reason why is the so-called “Ketogenesis” process, or the creation of ketones. [5]

What is Ketogenesis and when and why does it occur?

Every living person stores glycogen (a form of glucose) in the liver and muscles of the body. When you don’t consume carbs for a few hours the glycogen breaks down to glucose, and the liver releases this glucose in the blood. This way, the body prevents dangerously low blood sugar levels. [6]

The glycogen resources are depleted in about 24-32 hours after the last carbs consumption. [7] At this point, the liver initiates the production of water-soluble compounds as a source of energy, in order to maintain blood glucose levels. Those compounds are created from the breakdown of fats (either consumed fats or fats stored in the body), and are called “ketones.” [8]

What happens during gluconeogenesis?

Ketones can generate up to 70% of the energy needed by the body [9], and the other 30% of “body fuel” needed is created by the liver in a process called “gluconeogenesis.” [10]

In this process, the liver uses three elements:

  1. Amino acids (from proteins)

  2. Glycerol (from breaking down fats)

  3. Pyruvate and lactate (molecules, which are a consequence of glucose break down, but can be bound again to create glucose again)

This way, the liver compensates for the low consumption of carbs and enables the body to efficiently use energy with minimal glucose intake.


Several studies have looked into the health effects of the ketogenic diet, and various pieces of evidence suggest that it can be successfully used as part of treatment for obesity, insulin resistance, and other health conditions.

However, success with this diet is based on strict food restrictions, which may impact the ability to maintain this diet long term and to obtain a diverse and balanced diet. The numerous diet restrictions may cause vitamin and mineral deficiencies and malnutrition in healthy individuals.

Due to a low carbohydrate intake, a person following the ketogenic diet will likely end up consuming a low fiber diet, which impacts overall gut health and bowel regularity. Additionally, there are many healthy and unhealthy sources of fat that can contribute to the formation of ketones in the body. It is important to choose healthy unsaturated fat sources over saturated fats, to maintain a healthy fat profile during this period of prolonged fat intake.

This diet does cause fast weight loss, but there is limited evidence to show whether this diet is healthy long term or whether this weight loss is sustainable. For that reason, it’s essential to consult with your dietitian if you decide to “go keto”.


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