Keto Glossary: 29 Essential Keto Terms Defined

This glossary defines 29 keto terms in five groups: ketone chemistry, carbohydrates and macronutrients, metabolism, safety and measurement, and therapeutic use. Each entry links to a longer guide.

The vocabulary comes from biochemistry, nutrition labels, and laboratory testing. Distinctions such as ketosis versus ketoacidosis and net carbs versus total carbs matter because the paired terms are not interchangeable. Start with the science of ketosis, keto diet basics, or calculating your macros for context, then use this page for lookup.

Glossary concept map

Five concept families connect terms, measurements, context, and safety.

• Metabolism
• Measurement
• Labels
• Context
• Care

How to read a concept map

1. 1Concept
2. 2Measure
3. 3Source
4. 4Uncertainty or safety

Ketone chemistry

Ketone bodies are acetoacetate, D-BHB, and acetone. Hepatic production increases during fasting, sustained carbohydrate restriction, and some periods of prolonged exercise.

Term	One-line definition
Ketones (ketone bodies)	Acetoacetate, BHB, and acetone, a metabolically related group produced during ketogenesis.
Beta-Hydroxybutyrate (BHB)	A major circulating ketone body estimated by blood ketone meters; one result does not identify its cause.
Acetoacetate	The first ketone the liver produces; the one urine strips detect.
Acetone	A volatile ketone exhaled through the lungs that can contribute to fruity or solvent-like breath odor.

Carbs & macros

This cluster separates dietary targets from regulated label terms. “Net carbs” is informal arithmetic, and the correct starting value differs between US and EU/UK labels.

Term	One-line definition
Net Carbs	An informal label-based estimate whose arithmetic depends on the label system and selected adjustments.
Total Carbs	The regulated label carbohydrate value; US Total Carbohydrate includes fiber, while EU/UK Carbohydrate excludes fibre.
Macronutrients (Macros)	Fat, protein, and carbohydrate — energy-yielding nutrients distributed in different ways across ketogenic diets.
Sugar Alcohols (Polyols)	Carbohydrate sweeteners whose absorption, fermentation and glycemic effects differ by compound.
Glycemic Index	A relative, group-average glucose-response measure produced under standardized test conditions.
TDEE (Total Daily Energy Expenditure)	An estimate of the energy a person expends over a day.

Metabolism & mechanisms

These terms describe processes involved in glucose regulation, fat mobilization, fatty-acid oxidation, and ketone production. They interact through graded signals rather than one metabolic switch.

Term	One-line definition
Ketosis	A state of increased ketone production and use; glucose metabolism continues.
Gluconeogenesis	Regulated glucose production from lactate, glycerol, and glucogenic amino acids, mainly in the liver and renal cortex.
Glycogen	Stored glucose in liver and muscle; its contribution changes with intake, fasting, and activity.
Insulin	A hormone that suppresses lipolysis and ketogenesis while helping regulate blood glucose.
Lipolysis	The release of fatty acids and glycerol from stored triglycerides; it does not by itself show body-fat loss.
Fatty Acid Oxidation	The use of fatty acids as an energy substrate; it is distinct from net body-fat loss.
Insulin Resistance	Reduced tissue response to insulin, a central feature of type 2 diabetes.
Keto-Adaptation (Fat-Adapted)	An informal term for longer-running responses to carbohydrate restriction; markers and timing vary.

Safety & measurement

This cluster covers how ketosis is tested and, critically, how nutritional ketosis differs from the medical emergency ketoacidosis. Read the DKA entry first if you're worried about a symptom.

Term	One-line definition
Ketoacidosis (DKA)	A dangerous metabolic-acidosis emergency, most often in diabetes — not the same as nutritional ketosis.
Keto Flu	A non-diagnostic label for nonspecific symptoms reported after starting carbohydrate restriction; timing and causes vary.
Blood Ketone Meter	A finger-prick device that measures blood BHB at one point in time.
Ketone Urine Strips	Semi-quantitative strips that detect urine acetoacetate; hydration, renal handling, and timing affect the result.
Glucose Ketone Index (GKI)	Glucose mmol/L divided by blood BHB mmol/L; proposed for metabolic-therapy research without a validated wellness target.
Electrolytes	Charged minerals, including sodium, potassium, magnesium, and calcium, involved in fluid, nerve, and muscle function.
Sodium-Potassium Balance	The relationship between two electrolytes involved in fluid, blood-pressure, nerve, and muscle regulation.

Advanced & therapeutic keto

These terms cover supplements, informal cycling strategies, and clinician-directed ketogenic diet therapies. A higher ketone reading does not by itself establish body-fat loss, benefit, or safety.

Term	One-line definition
Exogenous Ketones	Supplemental ketone salts or esters that can acutely raise measured BHB without proving a broader outcome.
MCT Oil	A concentrated source of medium-chain triglycerides that can increase ketone production; it is optional.
Carb Cycling	An informal umbrella term for alternating lower- and higher-carbohydrate periods.
Therapeutic Ketogenic Diet	A clinician-directed dietary therapy whose formulation, monitoring, and target depend on the indication and program.

How is this glossary organized?

The 29 terms are grouped into five clusters — ketone chemistry, carbs and macros, metabolism, safety and measurement, and advanced or therapeutic keto — so related concepts sit together instead of in one long alphabetical list. Start with whichever cluster matches your question, then follow the internal links between entries; most terms cross-reference two to eight related terms.

If you're new to keto, start with keto diet basics and the science of ketosis for the full picture, then use this glossary as a lookup while you read. If you're dialing in your numbers, calculating your macros walks through the net-carb and macro math referenced throughout the Carbs & Macros cluster above.

Frequently Asked Questions

What's the difference between ketosis and ketoacidosis?

Nutritional ketosis does not ordinarily include metabolic acidosis. DKA requires diabetes or qualifying hyperglycemia, elevated ketones, and metabolic acidosis; euglycemic DKA can occur below 200 mg/dL, particularly with SGLT2-inhibitor use.

What are the three ketone bodies?

Beta-hydroxybutyrate (BHB), acetoacetate, and acetone. Blood meters estimate BHB, urine strips primarily detect acetoacetate, and breath devices estimate acetone; the methods are not interchangeable.

Is net carbs the same as the carbohydrate value on a label?

No. Net carbs is an informal estimate. On a US label, a method may subtract selected fiber, polyol or allulose adjustments from Total Carbohydrate. On an EU or UK label, Carbohydrate already excludes fibre, so fibre must not be subtracted again. There is no universal polyol deduction.

How is being fat-adapted different from just being in ketosis?

Ketosis describes increased ketone production and use. Keto-adaptation is an informal label for longer-running changes in fuel transport and oxidation; neither its markers nor its timing are standardized.

Do I need a blood ketone meter to do keto?

Routine measurement is generally unnecessary outside an individualized diabetes testing plan or a clinician-directed therapeutic protocol. A reading shows BHB at that moment, not diet quality, body-fat loss, benefit, or safety.