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What are Urine Ketones?

Urine ketones are byproducts of fat metabolism that appear when your body burns fat for energy instead of glucose. They are a normal finding during fasting or on a ketogenic diet, but high levels—especially in people with diabetes—can signal diabetic ketoacidosis (DKA), a medical emergency.

Understanding Ketones and Their Role in Your Body

Ketones are organic compounds produced by the liver during fat breakdown, a process called ketosis. This happens when glucose, your body’s primary fuel, is limited. There are three main types:

  • Acetoacetate
  • Beta-hydroxybutyrate
  • Acetone

Under typical conditions, glucose from dietary carbohydrates fuels most cells. During fasting, prolonged exercise, low-carb eating, or certain illnesses, the body switches to fat as the primary fuel source, producing ketones that can be detected in urine, blood, or breath.

Why Ketones Appear in Urine

If ketone production exceeds the body’s usage, the excess is excreted in urine (ketonuria). Common causes include:

  • Ketogenic or very low-carb diets
  • Extended fasting or severe calorie restriction
  • Intense or prolonged exercise
  • Pregnancy (especially with morning sickness)
  • Uncontrolled type 1 or advanced type 2 diabetes
  • Excessive alcohol intake
  • Vomiting, diarrhea, or other illnesses

Normal vs. Concerning Ketone Levels

  • Normal: Negative to trace (< 5 mg/dL)
  • Nutritional ketosis: Small to moderate (5–40 mg/dL)
  • Concerning (seek immediate care, especially if diabetic): Large (> 80 mg/dL)

Testing Methods and When to Test

Urine ketone testing can be done at home with test strips that change color based on ketone concentration. Steps:

  1. Collect a urine sample.
  2. Dip the strip briefly into the sample.
  3. Wait the instructed time.
  4. Compare the strip color to the chart provided.

Testing is recommended for people with diabetes when:

  • Blood glucose is > 240 mg/dL
  • Experiencing DKA symptoms: nausea, vomiting, abdominal pain, fruity-smelling breath
  • During illness or infection
  • Pregnant with gestational diabetes

For nutritional ketosis, many test in the morning or 3–4 hours after meals. Note: Urine testing becomes less accurate as the body adapts to ketone use.

Health Implications and Management

For healthy individuals, mild to moderate ketonuria during fasting or ketogenic diets is usually benign and may be linked to benefits such as fat loss and mental clarity. In diabetes, however, high ketones can mean DKA, which requires emergency care.

DKA Warning Signs

  • High blood glucose
  • Large ketone levels
  • Rapid breathing
  • Confusion or lethargy
  • Dehydration

Managing Ketone Levels

  • Stay well-hydrated
  • Monitor blood glucose closely if diabetic
  • Adjust insulin per medical advice
  • Avoid strenuous exercise when ketones are high
  • Seek prompt medical care for high ketones with symptoms

Regular biomarker testing—especially in people with diabetes—can help track metabolic changes and detect issues early, guiding dietary and medical decisions.

DISCLAIMER: IF YOU HAVE DIABETES AND DETECT MODERATE TO HIGH KETONES, SEEK MEDICAL CARE IMMEDIATELY.