What Is Keto?

Keto is an eating pattern designed to lower carbohydrate enough to increase the liver's production of ketone bodies. That metabolic state is called nutritional ketosis. It is a description of fuel use—not proof that someone is losing body fat, improving health, or following one universal fat-protein-carbohydrate ratio.¹²

In practical terms, keto usually means replacing many carbohydrate-rich foods with a planned mix of protein foods, non-starchy vegetables, and fats. The amount of carbohydrate that changes ketone production varies by the person, the food pattern, medication, activity, and the purpose of the plan. A clinical ketogenic diet for epilepsy is also different from a self-directed diet for weight or glucose management.²⁵

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.

Nutritional ketosis is not diabetic ketoacidosis

Both states involve ketones, but they are not interchangeable. Nutritional ketosis does not ordinarily include metabolic acidosis. Diabetic ketoacidosis (DKA) is a medical emergency defined by a combination of diabetes or qualifying hyperglycemia, elevated ketones, and metabolic acidosis—not by a ketone result alone.³

Question	Nutritional ketosis	Diabetic ketoacidosis (DKA)
Why are ketones present?	Carbohydrate or energy availability is low enough to increase ketone production.	Insulin action is insufficient and ketones rise with metabolic acidosis.
Can a home ketone reading diagnose it?	No; it only measures one part of metabolism at one point in time.	No; diagnosis requires clinical assessment and laboratory criteria.
What should you do with concerning symptoms?	Do not assume they are a normal adjustment.	Seek urgent assessment for persistent vomiting, abdominal pain, deep or difficult breathing, confusion, fainting, or marked drowsiness.

SGLT2 inhibitors can be associated with ketoacidosis at glucose levels lower than many people expect. Anyone with diabetes, pregnancy, illness, dehydration, or an SGLT2 prescription should treat warning symptoms as urgent rather than use a normal-looking glucose number for reassurance.³⁴

Before you start: take one safety action

Pause before sharply reducing carbohydrate if you use insulin, a sulfonylurea, or an SGLT2 inhibitor; have diabetes, kidney or liver disease, a history of an eating disorder, or are pregnant or breastfeeding. Ask the clinician responsible for your care whether keto is appropriate and what should be monitored. Do not stop or adjust a medicine to make a diet fit.²

If none of those apply, begin by clarifying your goal and reviewing the safety screen—not by chasing a ketone number. Is keto right for you? lays out the questions to take to a qualified clinician when relevant.

What the evidence does—and does not—say

The clearest established clinical role for ketogenic diet therapy is in selected drug-resistant epilepsies, where it is introduced and monitored by a specialist team.⁵ For body weight or type 2 diabetes, the evidence supports individualized decision-making rather than a universal keto prescription. Carbohydrate reduction can help some people manage glucose, but medication safety, food quality, fiber, lipid response, and whether the pattern is sustainable still matter.²⁶

That is why this guide uses direct research papers and clinical guidance, names uncertainty, and does not turn a mechanism into a promise. Ketosis itself is not a diagnosis, treatment, or measure of success.

Your 10-step keto foundation

Read this sequence from top to bottom. It moves from the definition and safety screen to food and planning decisions, so a meal plan does not appear before you know whether it makes sense to start one.

Guided path

Keto foundations

Understand the eating pattern, check whether it is appropriate to start, then build a practical first-week plan.

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Continue with: Keto Diet 101

1. 1
   Keto Diet 101

   Start with the definition, evidence, and basic setup.

2. 2
   Is Keto Right for You?

   Use the safety-first decision guide before changing your diet.

3. 3
   The Science of Ketosis

   Learn what nutritional ketosis does—and does not—mean.

4. 4
   Keto Diet Benefits

   Separate the evidence from broad health claims.

5. 5
   Potential Side Effects

   Know common adjustment effects and red flags that need care.

6. 6
   Keto Food List

   Turn the concept into a food-first shopping framework.

7. 7
   Calculating Your Keto Macros

   Use an individualized estimate instead of a universal ratio.

8. 8
   Keto Step-by-Step Guide

   Put the basics together in a paced, practical sequence.

9. 9
   Keto Grocery Shopping List

   Prepare a practical list before you shop for the first week.

10. 10
    7-Day Keto Meal Plan

    Use a flexible sample menu after you understand the setup.

Continue with a focused question

After the foundation

• Foundation

  Keto Diet 101

  Read the complete beginner guide to ketosis, evidence, food quality, and monitoring.

• Mechanism

  The science of ketosis

  See how carbohydrate availability, fatty-acid oxidation, and ketone bodies relate.

• Safety

  Potential keto side effects

  Separate expected adjustment questions from symptoms that need clinical attention.

Sources

1. Puchalska P, Crawford PA. Multi-dimensional Roles of Ketone Bodies in Fuel Metabolism, Signaling, and Therapeutics. Cell Metabolism. 2017;25(2):262–284. https://pubmed.ncbi.nlm.nih.gov/28178565/
2. American Diabetes Association Professional Practice Committee. Facilitating Positive Health Behaviors and Well-being to Improve Health Outcomes: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1):S89–S131. https://pubmed.ncbi.nlm.nih.gov/41358898/
3. Umpierrez GE, Davis GM, ElSayed NA, et al. Hyperglycaemic crises in adults with diabetes: a consensus report. Diabetologia. 2024;67(8):1455–1479. https://pubmed.ncbi.nlm.nih.gov/38907161/
4. U.S. Food and Drug Administration. FDA revises labels of SGLT2 inhibitors for diabetes to include warnings about too much acid in the blood. 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
5. National Institute for Health and Care Excellence. Epilepsies in children, young people and adults: non-pharmacological treatments. Updated January 30, 2025. https://www.nice.org.uk/guidance/ng217/chapter/non-pharmacological-treatments

Article history

1. August 24, 2026First published