What Are Ketones?

Ketogenic diets (also called the ‘keto’ diet) are a common approach used by those who wish to lose weight.

Those who champion the diet, do so as they believe that the metabolic state it leads to (ketosis) is effective for weight loss (1,2).

You can even buy exogenous ketone supplements that push you into ketosis, although keep in mind that these supplements are not regulated

Ketosis happens when carbohydrate intake in the diet is drastically reduced and is mainly replaced with fat. This is different from a standard low carbohydrate diet.

Carbohydrate is the preferred source of fuel for the body and, in particular, the brain. When carbohydrates are stored in the body, they are done so in the form of glycogen, which is made up of connected molecules of glucose.

As there is little glycogen for the body to use for energy when on a ketogenic diet, the body turns to fat as its primary energy source.

As with any changes to your diet, it is important to consider how sustainable it will be for you.

You can speak to a healthcare professional about the safest way to lose weight sustainably. A registered dietitian or registered nutritionist is best qualified to provide this advice. You can also check out some more tips for weight loss when you have diabetes in this article.

While following a ketogenic diet does produce ketones in the blood, this is not dangerous for people who do not have diabetes. For those who produce insulin effectively, the build-up of ketones in the blood does not lead to the blood becoming acidic, as it does in diabetic ketoacidosis (DKA) (1).

DKA is a serious condition that can affect people with diabetes mellitus. It occurs when ketone levels build up in the blood, and the blood gets acidic (3).

In this article, we will discuss the significance of ketones for people with diabetes. We will look at the role of ketones in diabetes, DKA, how it is caused, and how to prevent it.

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What are ketones?

Ketones are types of organic compounds that your liver produces when it burns fat for energy (3).

Low levels of ketones in your blood are not a problem, but if you treat your diabetes with insulin, you need to be aware of the risk of having high ketone levels. High levels of ketones are harmful to the body (4).

Types of ketones and DKA

There are two main types of ketones in the blood, and a third (acetone), which is the least abundant. The two types of ketones present in the most significant quantities are:

  • acetoacetate (AcAc)

  • 3-beta-hydroxybutyrate (3HB)

When ketones build up in the body, it can lead to something called diabetic ketoacidosis (DKA). DKA is a serious condition where the high ketone levels in your blood lead to it becoming acidic (having a low pH).

DKA can cause you to become unconscious, also known as a diabetic coma. This is an emergency, and you should call for medical help immediately if this is confirmed or suspected (5,6).

The role of ketones in diabetes

There are always some ketones in our blood, and the levels of each type will vary and are usually regulated naturally. Levels do increase during periods of fasting and prolonged exercise, and during pregnancy(3).

The most common clinical cause of high levels of ketones in the blood is diabetes. As we have already mentioned, DKA is a serious condition. It affects people who are living with diabetes, although mainly those who have type 1 diabetes.

Less commonly, DKA can also affect people with type 2 diabetes who take insulin. For those people, it is still essential to look out for the signs of DKA(3).

DKA is also common amongst those with undiagnosed type 1 diabetes. In fact, 23% of children are diagnosed with type 1 diabetes in DKA(7). If left untreated, it can be fatal(3,7).

Understandably, this is a concern for people living with diabetes. Yet, by understanding the role that ketones have to play in diabetes, knowing what to look out for, and how to treat symptoms of DKA, it can be prevented.

What causes high ketone levels?

Low levels of ketones in your blood are not a problem. Yet, if you manage your blood glucose levels with insulin, you need to be aware of the risk of having high ketone levels. As discussed, high levels of ketones in the blood can lead to DKA.

In DKA, high levels of ketones are produced in response to low insulin levels. Hormone balance also plays a part, although the most important thing is to understand your insulin treatment (8).

When you take insulin to control your blood glucose levels, your body should then be using this insulin effectively. This is essential for the management of diabetes, either type 1 or insulin-controlled type 2 diabetes.

A fundamental way that it does that is to convert your blood glucose into energy. If you don’t have enough insulin in your body to do that, you will start to use fat for energy instead.

When you do this, your body starts to produce ketones. This is done in the liver and can lead to acidic blood, and DKA.

When you take insulin, it is essential to remember the effect that things other than food can have on your blood glucose levels. Sometimes, you will need more insulin than you think, even if you’re intake of carbohydrates is unchanged.

Some things, aside from what you eat that can cause your blood sugar to rise further are(4,6):

  • Being unwell, for example, having an infection

  • Being pregnant

  • Recovering from surgery or injury

You can read more about the various causes of high blood sugar, and how best to manage them, here.

Another possible reason for high ketone levels in those with diabetes are:

  • Not having eaten enough food

Sometimes, you may not eat as much as normal. For example, if you are not feeling very well, or you miss a meal. This can sometimes lead to high ketone levels.

Aim to eat regular meals. If you are planning on eating less than normal, remember to adjust your insulin levels to account for this.

These are the main reasons for moderate to high levels of ketones in the blood (3,4). Read on to find out what to look out for when it comes to DKA.

Symptoms of high ketones

The best way to stop diabetic ketoacidosis is to prevent the build-up of ketones in the blood to start with.

This is not always possible, so in these cases, you need to be aware of the symptoms of high ketones levels in the blood.

The following are things to look out for if you think that you may have a build-up of ketones in your blood or your urine (9).

High blood sugar (also called hyperglycemia).

Having high blood sugar levels does not automatically mean that ketones will accumulate to dangerous levels in your blood.

If you are experiencing high blood sugar levels, testing your ketone levels will help you to see if you are at risk of developing DKA.

  • High levels of ketones in the urine

  • Frequent urination

  • Feeling very thirsty

These three things are usually early symptoms. After the early symptoms, others that may appear are:

  • Being more tired than usual

  • Difficulty breathing

  • Confusion

  • Feeling faint

  • Breath that has a fruity smell (this is the ketones on your breath)

  • Nausea/vomiting

  • Stomach pain

Once nausea and vomiting have started, the full extent of the condition can develop in a matter of hours (3,4,9). It is important to reiterate that DKA is serious.

If you have insulin-controlled diabetes and notice any of these symptoms, especially if you have high blood sugars, do not hesitate. Contact an emergency medical department immediately.

Testing high ketone levels

Regular testing of blood sugar levels is essential for people living with diabetes. This is especially important for those who manage their condition with insulin.

You can also test for ketones in your blood or your urine using test strips, although blood testing is more accurate. Urine testing will provide ketone levels within the last few hours, whereas a blood test will provide a ‘real-time’ result.

You can use the following as a guide for levels to watch out for when testing your blood sugars and ketone levels.

You should check your ketone level if your blood sugar is 11mmol/L or greater. When testing your blood ketone levels:

  • Lower than 0.6mmol/L is normal

  • 0.6 – 1.5mmol/L means you’re at a slightly increased risk of DKA. Test again in a few hours.

  • 1.6 – 2.9mmol/L means you’re at an increased risk of DKA. Contact your doctor or specialist diabetes team immediately.

  • 3mmol/L or above means you’re at a very high risk of getting DKA. You’re recommended to seek medical help immediately.

If you’re doing a ketone test from a urine sample, a result of 2+ means there is a high chance that you have DKA. Urine testing is done with a test strip. You pee on the strip and match the color that it changes to with the colors on the chart.

If you have type 1 diabetes and live in the UK, you should get a ketone monitor for free. Don’t hesitate to speak to your specialist team if you want to know more about testing for ketones, or need to know your targets.

Complications of high ketones

There are several possible complications of DKA (9). In children, cerebral edema (swelling on the brain) is the most common and leads to the most fatalities (7,9). Other possible complications are (9):

  • Low levels of potassium (hypokalaemia). If potassium levels in the blood become too low, it can cause serious problems. It can lead to muscle weakness and heart problems. Like cerebral edema, deficient potassium levels can be fatal.

  • Fluid on the inside of your lungs

  • Kidney damage

Treatment for high ketones

It is quite normal to be admitted to the hospital if you have been diagnosed with DKA.

Treatments include (9):

  • Insulin treatment, usually delivered via a drip, straight into a vein

  • Rehydration treatment (fluids delivered into a vein)

  • Replacement of any lost nutrients, particularly electrolytes

It is also vital that you are in the hospital when you have DKA so that you can be closely monitored. Your medical team will be looking out for signs of any of the complications discussed above, and if necessary, will treat those accordingly.


It is understandably scary to learn about DKA when you are living with diabetes. Yet, there are some steps you can take to prevent yourself from getting DKA. The following tips can help reduce your chances of getting DKA:

  • Take your insulin. You should stick to your agreed treatment plan unless advised by or agreed with a health care professional who knows your history and your diabetes management.

  • Always check with a doctor or pharmacist before taking new medications, as some can increase the risk of DKA.

  • Check your blood sugar regularly, so if it increases, you can spot it, and treat it – fast.

  • Seek help if you find it challenging to prevent high blood sugars

  • Be extra careful when you’re ill. This includes regular checking of blood sugar levels, ketone levels and ensuring you have someone who can support you


Ketones are organic compounds produced by your liver. They are produced when your body burns fat for energy instead of the preferred carbohydrate, and for people living with diabetes, they can be harmful to the body.

When levels of ketones build-up, it can lead to DKA. DKA is a serious condition, and those who have diabetes and treat it with insulin should be aware of it.

By understanding the symptoms, how to prevent it, and how to treat it, you can reduce the risks of DKA significantly.

Explore More


Diabetic Ketoacidosis (DKA): Causes, Symptoms, Treatments.


  1. Diabetes UK. Ketones and diabetes. 2019. Ketones and weight loss. (Online). https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/ketones-and-diabetes accessed on 06/12/2019
  2. Paoli, A (2014). Ketogenic Diet for Obesity: Friend or Foe? Int J Environ Res Public Health. 2014 Feb; 11(2): 2092–2107. doi: 3390/ijerph110202092
  3. American Diabetes Association. 2019. DKA (ketoacidosis) & ketones. (Online). https://www.diabetes.org/diabetes/complications/dka-ketoacidosis-ketones accessed on 06/12/2019
  4. Diabetic Ketoacidosis. 2017. (Online). https://www.nhs.uk/conditions/diabetic-ketoacidosis/ accessed on 06/12/2019.
  5. Diabetes UK. What is DKA (diabetic ketoacidosis)? 2019. (Online). https://www.diabetes.org.uk/guide-to-diabetes/complications/diabetic_ketoacidosis accessed on 07/12/2019
  6. Laffel, L (1999). Ketone bodies: a review of physiology, pathophysiology and application of monitoring to diabetes. Diabetes Metab Res Rev.1999 Nov-Dec;15(6):412-26
  7. Diabetes UK. Ketones and diabetes. 2019. (Online). https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/ketones-and-diabetes accessed on 06/12/2019
  8. Evans, K. 2019. Diabetic ketoacidosis. Update on management. Clin Med (Lond). 2019 Sep; 19(5): 396–398.doi: 7861/clinmed.2019-0284
  9. Hallett, A, Modi, A, and Levy, N (2016). Developments in the management of diabetic ketoacidosis in adults: implications for anaesthetists. BJA Education, 16 (1): 8–14 doi: 10.1093/bjaceaccp/mkv006

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