What does ketosis mean?
Ketosis is a metabolic condition in which the body relies heavily on fatty acids and forms ketone bodies, including acetone, acetoacetate, and beta-hydroxybutyrate. These compounds can supply energy when carbohydrate use is limited, as may happen during prolonged fasting or a low-carbohydrate diet. In nutritional or dietary contexts, ketosis is generally a controlled and reversible state, although it can cause symptoms such as headache, fatigue, nausea, or bad breath. The word is also used in medical discussions of diabetes, but it must be distinguished from ketoacidosis, a potentially life-threatening complication marked by severe metabolic imbalance and increased blood acidity. Understanding the distinction is important because claims about the benefits or risks of ketogenic diets concern nutritional ketosis, not the acute condition diabetic ketoacidosis.
nounKetosis is a metabolic state in which the body increases its use of fatty acids for energy and produces excess ketone bodies, which serve as alternative fuel for tissues such as the brain. It can occur during prolonged fasting, carbohydrate restriction, or some medical treatments, and is distinct from the potentially life-threatening condition diabetic ketoacidosis.
- The metabolic state or process of producing and using ketone bodies as an alternative source of energy, typically when carbohydrate availability is low.
"After several days of strict carbohydrate restriction, the dietitians monitored him for ketosis and other signs of nutritional imbalance."
"The study examined whether nutritional ketosis could improve the athletes' endurance performance."
"Her doctor explained that moderate dietary ketosis was different from the ketoacidosis associated with uncontrolled diabetes."
The plural is uncommon because the word is normally used in the singular in medical and nutritional contexts.
"The textbook briefly discusses ketoses and their role in carbohydrate metabolism."
Ketosis lets the body run on fat, but the name does not describe the dangerous ketoacidosis that can complicate diabetes.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does ketosis come from?
Ketosis combines the combining form keto-, associated with ketones, with the suffix -osis, a Greek-derived term denoting a condition or process. The word follows the modern medical tendency to name bodily conditions with Greek elements. It is related to ketone and the closely associated terms ketogenesis and ketogenic.
Related word forms
How ketosis is actually used
In general health contexts, the term is usually used in connection with fasting, carbohydrate restriction, or ketogenic diets. It is predominantly a medical or nutritional term rather than everyday vocabulary, and it should not be used as a synonym for ketoacidosis.
Easily confused with ketosis
Ketosis is a metabolic state that may be intentional or nutritionally induced, whereas ketoacidosis is a dangerous medical condition involving severe metabolic disturbance and excessive acidity.