What is "ketosis"

1900, from keto-, comb. form of ketone, + -osis.

n. (context pathology English) A metabolic state in which the body produces ketones to be used as fuel by some organs so that glycogen can be reserved for organs that depend on it. This condition occurs during times of fasting, starvation, or while on a ketogenic weight-loss diet.

n. an abnormal increase of ketone bodies in the blood as in diabetes mellitus [syn: ketonemia, acetonemia]

Ketosis is a metabolic state in which most of the body's energy supply comes from ketone bodies in the blood, in contrast to a state of glycolysis in which blood glucose provides most of the energy.

Ketosis is a nutritional process characterised by serum concentrations of ketone bodies over 0.5 mM, with low and stable levels of insulin and blood glucose.thefreedictionary.com/ketosis citing:

• The American Heritage® Medical Dictionary Copyright © 2007
• Mosby's Medical Dictionary, 8th edition. © 2009
• Dorland's Medical Dictionary for Health Consumers. © 2007 It is almost always generalized with hyperketonemia, that is, an elevated level of ketone bodies in the blood throughout the body. Ketone bodies are formed by ketogenesis when liver glycogen stores are depleted (or from metabolising medium-chain triglycerides). The main ketone bodies used for energy are acetoacetate and β-hydroxybutyrate, and the levels of ketone bodies are regulated mainly by insulin and glucagon. Most cells in the body can use both glucose and ketone bodies for fuel, and during ketosis, free fatty acids and glucose synthesis ( gluconeogenesis) fuel the remainder.

Longer-term ketosis may result from fasting or staying on a low-carbohydrate diet, and deliberately induced ketosis serves as a medical intervention for various conditions, such as intractable epilepsy, and the various types of diabetes. In glycolysis, higher levels of insulin promote storage of body fat and block release of fat from adipose tissues, while in ketosis, fat reserves are readily released and consumed. For this reason, ketosis is sometimes referred to as the body's "fat burning" mode.