Ketosis

Ketosis is a metabolic state in which the liver increases production of ketone bodies, principally beta-hydroxybutyrate (BHB) and acetoacetate, as carbohydrate or total energy availability falls. Ketones then provide part of the energy used by the brain and other tissues.¹

Medical disclaimer. This article is for general educational purposes only and is not medical advice. It is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider before starting the ketogenic diet or making changes to your diet, exercise, or medication — especially if you are pregnant or breastfeeding, take medication, or have a medical condition such as diabetes, or kidney, liver, or heart disease. See our editorial & medical-review policy.

What causes ketosis?

Ketone production rises during carbohydrate restriction, fasting, prolonged exercise, and other states in which fatty-acid delivery to the liver increases. Insulin normally restrains this process. The body continues to use glucose and to make glucose for tissues that require it; ketosis is not a complete switch from one fuel to another.¹

A ketone concentration is not a direct measure of body-fat loss, diet quality, or health benefit. It reflects production, use, and clearance at that moment. Food intake, fasting, exercise, illness, pregnancy, alcohol, medication, and test timing can all change the result.

How is ketosis different from DKA?

Nutritional ketosis does not ordinarily include metabolic acidosis. Diabetic ketoacidosis (DKA) is diagnosed when three components occur together: diabetes or glucose at least 200 mg/dL, elevated ketones, and venous pH below 7.3 and/or bicarbonate below 18 mmol/L.²

There is no single ketone value that can establish safety. Home ketone tests do not measure pH or bicarbonate, and euglycemic DKA can occur with glucose below 200 mg/dL. SGLT2 inhibitors, pregnancy, reduced food intake, illness, and alcohol-related impaired gluconeogenesis are recognized contexts for euglycemic DKA.²

Seek emergency care now for persistent vomiting, severe abdominal pain, deep or difficult breathing, confusion, fainting, or marked drowsiness. These signs are especially concerning for DKA with known or possible diabetes, pregnancy, or SGLT2-inhibitor use. The FDA specifically warns that SGLT2-associated ketoacidosis may occur without very high glucose.³

Does ketosis need to be measured?

Most people using a ketogenic diet for general purposes do not need to measure ketones. A blood ketone meter measures BHB directly. Urine strips measure acetoacetate and can lag behind the current blood state. Neither should be used to chase a higher number.

People at risk of DKA should follow the sick-day and testing plan supplied by their diabetes team. A clinical or therapeutic ketogenic-diet program may also prescribe condition-specific monitoring. Those are medical uses, not general targets.

Frequently Asked Questions

Does ketosis prove that body fat is being lost?

No. Ketones can be made from dietary fat as well as stored fat. Net body-fat loss depends on energy balance over time, not a ketone result.

Is a higher ketone reading better?

Not necessarily. There is no universally beneficial target band, and a higher value can have very different meanings depending on diabetes, symptoms, pregnancy, illness, medication use, fasting, and recent food intake.

Can DKA occur with normal-looking glucose?

Yes. Euglycemic DKA includes elevated ketones and metabolic acidosis with glucose below 200 mg/dL. SGLT2 inhibitors are an important medication-related risk.

Do I need a ketone meter for a keto diet?

Usually not. Routine measurement is unnecessary outside an individualized diabetes sick-day plan or a clinician-directed therapeutic protocol.

See also: Ketones · BHB · Ketoacidosis (DKA) · Blood ketone meter · Urine ketone strips · Detailed ketosis vs DKA guide · Full glossary

Works cited

1. Multi-Dimensional Roles of Ketone Bodies in Fuel Metabolism, Signaling, and Therapeutics — Puchalska P, Crawford PA, Cell Metabolism. 2017;25(2):262–284, doi:10.1016/j.cmet.2016.12.022 https://pmc.ncbi.nlm.nih.gov/articles/PMC5313038/
2. Hyperglycemic Crises in Adults With Diabetes: A Consensus Report — Umpierrez GE, Davis GM, ElSayed NA, et al., Diabetes Care. 2024;47(8):1257–1275, doi:10.2337/dci24-0032 — August 23, 2026 https://pmc.ncbi.nlm.nih.gov/articles/PMC11272983/
3. FDA revises labels of SGLT2 inhibitors for diabetes to include warnings about too much acid in the blood and serious urinary tract infections — U.S. Food and Drug Administration, revised March 15, 2022 — August 23, 2026 https://www.fda.gov/files/drugs/published/FDA-revises-labels-of-SGLT2-inhibitors-for-diabetes-to-include-warnings-about-too-much-acid-in-the-blood-and-serious-urinary-tract-infections.pdf

Article history

1. August 23, 2026Updated
2. August 18, 2026First published