Difference Between Ketosis and Ketogenesis

The key difference between ketosis and ketogenesis is that ketosis is the metabolic state that indicates elevated levels of ketone bodies in the blood or urine, while ketogenesis is the biochemical process where organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids.

Eukaryotic cells make energy by different processes such as photosynthesis, glycolysis, citric acid cycle and oxidative phosphorylation.  These processes result in energy-rich molecules like ATP and NADH. Organisms obtain different sources such as direct sunlight, CO₂ and organic food molecules, etc., from the environment in order to produce energy. Ketosis and ketogenesis are two processes related to energy production in cells.

CONTENTS

1. Overview and Key Difference
2. What is Ketosis 
3. What is Ketogenesis
4. Similarities Between Ketosis and Ketogenesis
5. Side by Side Comparison – Ketosis vs Ketogenesis in Tabular Form
6. Summary

What is Ketosis?

Ketosis is a normal physiological condition which is characterized by elevated serum ketones and normal blood glucose. In this condition, blood pH also remains normal. The increasing production of ketone bodies in the body is due to the low glucose availability. Therefore, an increase in the production of ketone bodies creates an alternate energy source for the brain. This condition can be a result of low-carbohydrate diets or fasting. When physiologic ketoacidosis is a result of restricting carbohydrate diets (ketogenic diets), it is sometimes referred to as nutritional ketosis. In ketosis, the ketone levels in the blood generally remain below 3 mM.

Ketogenic diets can help lose weight. In short, it loses weight very quickly since it reduces the body’s stores of glycogen and water. In the long term, ketogenic diets suppress appetite, leading to low-calorie intake. Sometimes, ketosis has several health benefits, such as reduced seizures in children with epilepsy. Over-the-counter supplements are reported to raise ketone levels in the body, and they come as pills, powders, oils, and other forms. In ketosis, the liver rapidly breaks down fatty acids into acetyl-CoA. The acetyl-CoA molecules can then be converted into ketone bodies such as acetoacetate, beta-hydroxybutyrate, and acetone, etc. These ketone bodies can serve as an energy source and signalling molecules.

What is Ketogenesis?

Ketogenesis is a biochemical process. Organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids. This process supplies energy to certain organs such as the brain, heart and skeletal muscle. This process even takes place under specific conditions, including fasting, caloric restriction, sleep, or others. Insufficient gluconeogenesis causes excessive ketogenesis and hypoglycemia. It ultimately leads to a life-threatening condition called non-diabetic ketoacidosis.

Ketone bodies are not obligately produced from fatty acids. A considerable amount of ketone bodies is synthesized only in a condition of carbohydrate and protein insufficiency, where only fatty acids are readily available as fuel for ketone bodies production. Ketogenesis constantly happens in healthy individuals. This process is under the control of a master regulatory protein called AMPK. It activates during times of metabolic stress, such as carbohydrate insufficiency. Ethanol is a potent inhibitor in AMPK.

What are the Similarities Between Ketosis and Ketogenesis?

• These processes produce ketone bodies.
• Both processes take place in situations such as carbohydrate restriction, fasting, excessive exercise, etc.
• Fatty acids participate in both processes.
• Both processes supply alternative energy to the brain.

What is the Difference Between Ketosis and Ketogenesis?

Ketosis is the metabolic state characterized by elevated levels of ketone bodies in the blood or urine. On the other hand, ketogenesis is the biochemical process where organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids. So, this is the key difference between ketosis and ketogenesis. Moreover, another important difference between ketosis and ketogenesis is that ketosis is a metabolic process, while ketogenesis is a biochemical process.

The below infographic shows more differences between ketosis and ketogenesis in tabular form.

Summary – Ketosis vs Ketogenesis

Ketosis is a metabolic process in which the body produces ketone bodies to be used as fuel by some organs such as the brain.  It is characterized by elevated serum ketones, normal blood glucose, and normal blood pH. Therefore, glycogen can be reserved for organs during conditions such as fasting, starvation, etc. Ketosis also occurs when following a ketogenic weight loss diet. In ketosis, the body’s acid-base homeostasis is maintained.  In contrast, ketogenesis is a biochemical process where organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids. The process supplies energy to certain organs under specific conditions such as fasting, caloric restriction, sleep or others. Insufficient gluconeogenesis and excessive ketogenesis can cause non-diabetic ketoacidosis. Thus, this is the summary of the difference between ketosis and ketogenesis.

Reference:

1. Khatri, Minesh. “Ketosis: Definition, Keto Diet, Symptoms, and Side Effects.” WebMD, WebMD, 15 May 2020, Available here.
2. Dhillon, Kiranjit K. “Biochemistry, Ketogenesis.” StatPearls [Internet]., U.S. National Library of Medicine, 17 Feb. 2021, Available here.

Image Courtesy:

1. “Ketones” By Zachary P. Christensen – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Ketogenesis” By Sav vas – Own workSources:File:Ketogenesis.pngFile:Acetyl-CoA.svgFile:Acetoacetyl-CoA.svgFile:Aceton.svgFile:Acetoacetate to beta-hydroxybutyrate.svgFile:HMG coenzyme A.svg (CC0) via Commons Wikimedia