Diabetes and Ketones

Ketones in the blood occurs when the body burns its own fat
Ketones in the blood occurs when the body burns its own fat

The presence of high levels of ketones in the bloodstream is a common complication of diabetes, which if left untreated can lead to ketoacidosis.

Ketones build up when there is insufficient insulin to help fuel the body’s cells.

High levels of ketones are therefore more common in people with type 1 diabetes or people with advanced type 2 diabetes.

If you are suffering from high levels of ketones and seeking medical advice, contact your GP or diabetes healthcare team as soon as possible.

What exactly are ketones, and what do they have to do with diabetes?

Ketones are an acid remaining when the body burns its own fat.

When the body has insufficient insulin, it cannot get glucose from the blood into the body's cells to use as energy and will instead begin to burn fat.

When the body is burning too much fat, it may cause ketones to become present in the bloodstream.

How do I test for ketones?

Ketone testing can be carried out at home.

There are several products that test for ketones in the urine as well as blood glucose meters which can test for ketones as well as blood glucose levels.

So, my body can’t get enough sugar. Why is this a problem?

Sugar is the primary fuel that the body uses for energy.

Insulin, a hormone produced in the pancreas that metabolises blood sugar, is either deficient or non-existent in the blood of diabetes patients.

If the body cannot burn sugar, it will burn stored fat, and ketone build up will begin.

When ketone levels become too high, the risk of ketoacidosis is raised, and this emergency condition can lead to coma and even death in serious cases.


Ketones are a compound that can provide the body with energy. Ketones are produced when the body breaks down fats and protein. The usual reason for ketones being produced is when the body has used up its stores of sugar.

The NHS states that without sugar available, the body needs to find energy from another source, so it breaks down fat to make ketones for energy.

In type 1 diabetes, there is another reason why ketones are produced - high blood sugar or hyperglycemia. Strictly speaking, it’s actually the lack of insulin for why ketones are produced in type 1 diabetes.

The body has loads of energy in the form of sugar, but without having insulin, the glucose can’t get into the cells to provide energy. As a result, the body switches to providing a different means of energy - ketones.

As with many things in the body, ketones are safe as long as the body doesn’t produce too much. Long term research studies, such as an 8 year study carried out by Johns Hopkins Children's Center, have showed that ketones are not inherently dangerous at low levels.

For most people, high ketone levels are relatively rare. But people with type 1 diabetes, however, are at a greater risk, especially if blood glucose levels go too high.

Ketoacidosis is a dangerous state which happens if ketone levels become high.  The signs of ketoacidosis include dehydration, laboured breathing and vomiting. Ketoacidosis, because it’s dangerous, should be treated as an emergency and calling for medical help is advised.

You can test for ketones and this is something which people with type 1 diabetes can find useful. Diabetes advise ketone testing for people with type 1 diabetes during illness if blood glucose levels go over 15 mmol/L.

Ketone tests can be done with urine test strips and some special blood glucose meters also test for ketones. If high ketone levels won’t come down, contact your health team for advice.

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I am type 2 diabetic, should I be tested for ketones?

As discussed above, all people with type 1 diabetes should be aware of the effects of ketones. Generally people with type 2 diabetes are less likely to suffer from high ketones because most people with type 2 will be producing sufficient insulin.

However, people with advanced type 2 diabetes, may not produce enough insulin and could be susceptible to high levels of ketones.

It is essential to know what the symptoms are, and when you should test for ketones. Finding ketones present in your urine is a sign that the management of your diabetes needs adjusting.

Ketone testing may also be advised pregnant diabetics and women who develop gestational diabetes.

When should I test for ketones, and how will this affect the management of my diabetes?

The following information is of relevance to people who need to take insulin.

Your GP or healthcare team will be able to inform you of the best possible time for you personally to test for ketones. However, it is generally understood that testing should take place when fasting (i.e: when food has not been consumed for eight hours or more) and any of the following occurs:

  • Blood sugar is on or above 13.9 mmol/l (250 mg/dl) for two consecutive tests
  • When any illness occurs (as even minor illnesses can cause ketones)
  • If you vomit or suffer from diarrhoea
  • You suffer from depression or stress
  • You fall pregnant

If you record high levels of ketones, contact your health team immediately for advice on how best to manage your diabetes.

The ketone test is simple and involves a dip and read urine test strip. If the colour changes, there are ketones in your urine.

Ketone test strips are available from the Diabetes Shop.

I am diabetic and my ketone test is positive, what should I do?

If the test shows low levels of ketones, under 0.6 mmol/L, you needn’t take any action.

If the test is above 0.6 mmol/L it is advisable to test again within an hour to see if the ketone level is rising.

If you record a ketone level above 1.5 mmol/L you should contact your healthcare team, and explain the situation to them.

Should the tests show very small amounts of ketones take the following actions:

  • Drink water every hour, and continue testing every three hours.
  • If your ketone levels do not fall after two tests contact your healthcare team.
  • If the test shows moderate or high ketone numbers then telephone your doctor at once, and drink water.

I think I might have diabetic ketoacidosis, how would I know?

If you are suffering from diabetic ketoacidosis the early signs are likely to include:

  • Stomach pains
  • Nausea and/or vomiting
  • Breathlessness
  • Breath that smells fruity

In this instance, call your doctor as soon as possible as ketoacidosis is an extremely severe condition.

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