All About Ketones and Diabetes

Ketones Occur When the Body Breaks Down Fat For Energy

Urine Testing
Peter Dazeley/Photographer's Choice/Getty Images.

It is important for people with diabetes to have an understanding of what ketones are and how to identify them. Ketones are organic compounds that result when body fat is broken down for energy. While this may not sound like a bad thing, for people with diabetes, especially Type 1 diabetes, high levels of ketones in the body can be toxic. Should you develop ketones, you need to know how to identify symptoms, how to check for them, and which levels are considered to be toxic.

When Do Ketones Occur in the Body?

Glucose is usually used by cells for energy. But, when there's no insulin to help transport it out of the blood and into the cells, the body has an "energy crisis" and starts to break down body fat into ketones as an alternative fuel source. High levels of ketones in the body can be toxic.

High blood glucose levels (over 250 mg/dl) are one sign that the body may have high levels of ketones circulating in the blood. This can progress to a serious complication called diabetic ketoacidosis. Ketoacidosis can occur in anyone with diabetes, but occurs more commonly in people with Type 1 diabetes. According to the American Diabetes Association, ketoacidosis can occur when:

  1. Your body does not have enough insulin either because you did not inject enough or you may need more than usual because you are sick.
  2. You are sick and are unable to eat enough food.
  3. Your blood sugar drops too low while you are sleeping and results in high levels of ketones in the morning. 

    For more information on ketoacidosis go to: Diabetes and Diabetic Ketoacidosis

    When Should You Check for Ketones? 

    Some experts recommend that you check for ketones when your blood sugar is repeatedly over 240 mg/dl for no apparent reason, while other sources say to check when you blood sugar is above 300 mg/dL.

    Ask your health care provider what's best for you. Another time to test for ketones would be if your blood sugar is high (250-300 mg/dL or more) and you are feeling ill (for instance, with cold or flu symptoms, nausea, vomiting, or excessive tiredness). 

    How Do You Check for Ketones? 

    Testing the urine is one way to check for ketones. Most pharmacies carry ketone strips or you can ask your physician to get you a prescription. Some blood glucose meters also check for ketones. Find out if your glucose meter can also measure your ketone levels. All people with Type 1 diabetes should have a way to measure ketones — if you don't ask your health care provider. 

    Are There Different Levels of Ketones? 

    Yes. Depending upon how long your body has been using fat for fuel you may have trace, small or moderate to high levels of ketones in your urine. If your results are trace or small this can mean that ketone buildup is starting and you can retest in a few hours. However, moderate or large amounts of ketones is dangerous and should result in a phone call to health care provider right away. If you are ever uncertain of what to do in the event of ketones, call you doctor immediately. Depending on the severity of the ketones and how you are feeling, you maybe instructed to hydrate and take more insulin or be told to go to the emergency room.

    What Are the Warning Signs of Ketoacidosis? 

    Ketoacidosis can happen in anyone with diabetes, though it is rare in people with Type 2 diabetes and more common in those people with Type 1 diabetes (because they do not make any insulin). 

    Ketoacidosis usually happens slowly, but in the event you are vomiting and having symptoms you should seek emergency help right away. The following are early symptoms: 

    • Thirst or a dry mouth
    • Frequent urination
    • High blood glucose (blood sugar) levels
    • High levels of ketones in urine

    Other symptoms that can occur include: 

    • Constant tiredness
    • Dry or flushed skin 
    • Nausea, vomiting or abdominal pain
    • Difficulty breathing 
    • Fruity odor on breath 
    • Confusion or difficulty paying attention

    For More Information on When High Blood Sugar Can Be an Emergency: 

    Hyper and Hypoglycemia Emergencies in Diabetes


    American Diabetes Association.DKA (Ketoacidosis) and Ketones.

    American Diabetes Association. Checking for Ketones.