Ketonuria: What It Means and How to Manage It

Ketonuria is a medical term that means ketones are present in your urine. It’s a signal that your body is breaking down fat instead of carbohydrates for energy. While this can happen during fasting, low-carb diets, or exercise, it can also be a warning sign of an underlying condition like diabetes or metabolic imbalance.

Understanding why ketones appear in your urine and what they mean for your health is key to managing the condition safely.

This article explains what causes ketonuria, how it’s diagnosed, when it’s dangerous, and what to do if you have it.

What Are Ketones?

Ketones are chemicals made by the liver when your body breaks down fat for energy. Normally, your body uses glucose (sugar) as its main fuel. When glucose levels are low — due to fasting, carbohydrate restriction, or insulin deficiency — the body switches to burning fat, producing ketones as a byproduct.

A small amount of ketones in the urine may be harmless or even expected, especially for people on ketogenic diets. However, high levels can indicate that your body lacks enough insulin to use glucose properly — a situation that can become dangerous.

Learn how the liver produces and regulates ketones in our At-Home Liver Tests Guide.

Causes of Ketonuria

There are several possible reasons ketones appear in urine:

1. Diabetes (Especially Type 1)

When the body lacks insulin, glucose cannot enter the cells. As a result, fat is broken down for energy, producing ketones. High levels of ketones in people with diabetes may indicate diabetic ketoacidosis (DKA), a medical emergency.

2. Fasting or Starvation

When you go long periods without eating, your body burns fat for fuel. Mild ketonuria can occur during fasting or severe calorie restriction.

3. Low-Carbohydrate or Ketogenic Diets

Ketonuria is common among people following keto or Atkins-style diets, as carbohydrate intake is intentionally reduced. In this case, it’s typically not harmful.

4. Prolonged Vomiting or Diarrhea

Loss of fluids and electrolytes can deplete carbohydrate stores, leading to temporary ketonuria.

5. Alcohol Use Disorder

Heavy drinking can cause alcoholic ketoacidosis, a serious condition that elevates ketones and acid levels in the body.

6. Hyperthyroidism or Infection

Serious illness or high thyroid hormone levels can increase metabolism and fat breakdown, sometimes leading to ketonuria.

To understand how glucose levels contribute to this, read our Guide to Understanding Glucose in Urine.

Symptoms of Ketonuria

Symptoms depend on the underlying cause and the level of ketones. Mild cases may have no symptoms at all, while severe ketonuria (especially with diabetes) can be life-threatening.

Common symptoms include:

• Frequent urination or dehydration.

• Fatigue or weakness.

• Nausea or vomiting.

• Fruity-smelling breath.

• Rapid breathing.

• Confusion or difficulty concentrating.

• Abdominal pain.
  
  

If you have diabetes and experience these symptoms, check your blood sugar and ketone levels immediately and contact your healthcare provider.

Track these changes safely using the Ribbon Checkup Urine Test to monitor ketone and glucose balance at home.

Diagnosing Ketonuria

Ketonuria is usually detected using a urine test.

1. Urine Ketone Test Strips

These over-the-counter test strips change color in response to ketones. They provide a quick way to check for ketonuria at home.

2. Laboratory Tests

Doctors may use urine analysis or blood ketone testing to measure the exact concentration of ketones. Blood tests are more accurate for identifying serious complications like diabetic ketoacidosis.

3. Additional Blood Tests

If ketonuria is detected, your doctor may also check:

• Blood glucose levels.

• Electrolyte balance.

• Kidney function tests.

You can easily do this yourself with the Ribbon Checkup Urine Test — it measures ketones, glucose, and other key markers.

Is Ketonuria Dangerous?

The seriousness of ketonuria depends on the cause.

• In diabetes: It can be a warning sign of diabetic ketoacidosis (DKA) — a life-threatening condition where high ketone and glucose levels make the blood acidic. DKA requires emergency treatment.

• In fasting or dieting: Mild ketonuria is usually harmless and indicates the body is burning fat.

• In illness or alcohol abuse: It may signal metabolic imbalance or dehydration, requiring medical evaluation.
  
  

If you’re unsure why you have ketonuria, always seek medical advice — especially if symptoms appear.

Alcohol also affects liver detoxification — explore the At-Home Liver Tests Guide to understand how your liver responds.

Treating Ketonuria

Treatment focuses on the underlying cause.

1. If You Have Diabetes:

• Check blood sugar and ketones frequently.

• Never skip insulin doses.

• Drink plenty of fluids to stay hydrated and help flush out ketones.

• If ketones remain high or you feel sick, seek emergency care — DKA can develop quickly.
  
  

2. If Due to Fasting or Dieting:

• Reintroduce carbohydrates gradually.

• Eat balanced meals with complex carbs, proteins, and healthy fats.

• Stay hydrated to help the kidneys remove excess ketones.
  
  

3. If Due to Alcohol or Illness:

• Rehydrate and replenish electrolytes.

• Treat the underlying illness.

• Seek medical help if vomiting, confusion, or severe weakness occurs.
  
  

Preventing Ketonuria

You can lower your risk by:

• Managing diabetes carefully: Monitor glucose and follow your insulin plan.

• Avoiding extreme fasting or crash diets.

• Staying hydrated, especially during illness or hot weather.

• Eating regular, balanced meals.

• Limiting alcohol consumption.
  
  

If you’re on a low-carb or ketogenic diet, check your ketone levels periodically and consult your healthcare provider to ensure your body is adapting safely.

Also review your kidney health with our Complete Guide to At-Home Kidney Function Tests — kidneys play a vital role in clearing ketones from the body.

When to Seek Medical Help

Call your doctor or go to the emergency room if you experience:

• Persistent vomiting.

• Deep or rapid breathing.

• Fruity breath odor.

• Severe weakness, fatigue, or confusion.
  
  

These symptoms could indicate diabetic ketoacidosis, which requires urgent treatment with insulin and fluids.

The Bottom Line

Ketonuria simply means ketones are present in your urine — but the reason matters. It can be harmless in cases of dieting or fasting, or dangerous in conditions like diabetic ketoacidosis.

Monitoring your blood sugar, eating regularly, and staying hydrated can prevent most cases. If you have diabetes, checking your ketone levels when you’re sick or your glucose is high is a critical safety step.

Understanding what causes ketonuria helps you take action early, prevent complications, and protect your long-term health.

Want to check your metabolic health from home?
You can take an at-home metabolic and diabetes health test through Ribbon Checkup and get results in days.

Explore metabolic health tests 

Related Resources

Want to dive deeper into kidney health? Check out these helpful reads:

• The Complete Guide to At-Home Kidney Function Tests – Stay on top of kidney health with simple home testing.
  
  

• How Long Do Kidney Stones Last? Must Know – Get clarity on how long kidney stones typically last.
  
  

• What Can Mimic Kidney Stone Pain? – Learn about other conditions that cause similar pain.

References

References

• Kim, B. R., Joo, N.‑S., & et al. (2020). The presence of urinary ketones according to metabolic health status: A population‑based study. Journal of Korean Medical Science, 35, e273. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7416001/

• Luethi, N., Cioccari, L., Crisman, M., Bellomo, R., Eastwood, G. M., & Mårtensson, J. (2016). Prevalence of ketosis, ketonuria, and ketoacidosis during liberal glycemic control in critically ill patients with diabetes. Critical Care, 20, 297. https://ccforum.biomedcentral.com/articles/10.1186/s13054-016-1462-7

• Mechchate, H., & et al. (2025). Ketone bodies in renal function and diabetic kidney disease. Biochemical Pharmacology. https://www.sciencedirect.com/science/article/pii/S0955286325000786

• NCBI Bookshelf (Authors unspecified). (n.d.). Ketonuria. In Clinical Methods: The History, Physical, and Laboratory Examinations (3rd ed.). National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/books/NBK247/

• Medical News Today. (2023, October 30). What to know about ketones in urine. https://www.medicalnewstoday.com/articles/ketones-in-urine

• Cleveland Clinic. (2024). Ketones in urine: Causes, symptoms & treatment. https://my.clevelandclinic.org/health/articles/ketones-in-urine

• Healthline. (2020, June 1). Ketonuria: What you need to know. https://www.healthline.com/health/ketonuria

• MedlinePlus. (2024). Urine ketones test. U.S. National Library of Medicine. https://medlineplus.gov/lab-tests/ketones-in-urine/

• RxList. (2020). Ketonuria: Definition, diagnosis, treatment. https://www.rxlist.com/ketonuria/definition.htm