Technically, ketones are organic compounds that contain a carbonyl group (a carbon atom double bonded to an oxygen atom) that is single bonded to two hydrocarbon groups made by oxidizing secondary alcohols. (Don’t worry, no one will be testing you on this later.)
Millions of different ketones can potentially be created, but what we care most about are the ketones that can be formed in our bodies, the ketones that are also known as ketone bodies.
The three ketone bodies are:
- Acetoacetate
- Beta-hydroxybutyrate (BHB)
- Acetone
These ketone bodies are made from fatty acids and ketogenic amino acids via a process called ketogenesis. When sugar is scarce and gluconeogenesis can’t keep up with our energy needs, the liver starts using ketogenesis to form acetoacetate.
Acetoacetate is then converted into either BHB or acetone. Acetone is the least abundant ketone body, but it may be produced in higher quantities when you first start the ketogenic diet. This is the reason why many people get “keto breath” when they first begin restricting carbs.
As your body adapts to the ketogenic diet, BHB will become the most prevalent ketone body and your brain and muscle cells will start using it as their primary fuel (and you will no longer have keto breath or other keto flu symptoms).
If you would like to learn more about ketones and ketone bodies, click here.