What are Ketones

Ketones are an extremely efficient fuel source for not just your body, but also your brain, which is why people say ketones give them more energy and mental clarity.


In this blog we’ll explore what ketones are, the different types of ketones, things commonly mistaken for ketones, how to test for ketones, and what your ketone levels should be.


What are Ketones? Forever Keto

So what are Ketones?

Ketones are produced by your liver when it breaks down fat. They are a naturally produced chemical that your body can use for energy, at anytime, not just on a Keto Diet.


If you run out of glucose from carbohydrates - typically stored in the body as glycogen - your body will turn to stored fat for energy. This fat is broken down, producing ketones.


Ketones are good on a Keto Diet, but if they appear in too high levels it could be a sign that you're at risk of developing Diabetic Ketoacidosis (DKA), which could lead to dangerous conditions like Diabetes and an increased risk of heart disease and stroke over time.


23% of children diagnosed with Diabetes are in Diabetic Ketoacidosis so parents should pay particular attention for the symptoms of Ketosis in children, which could indicate DKA.

SEE 10 SIGNS YOU’RE IN KETOSIS


There are 2 Types of Ketones

Naturally produced Endogenous Ketones - acetoacetic acid, beta-hydroxybutyrate and acetone. These endogenous ketones are produced as a result of intensive exercise, during fasting, or on certain restricted diets - like Keto.

Ketones are an extremely efficient fuel source for not just your body, but also your brain, which is why people say ketones give them more energy and mental clarity.


Exogenous Ketones are Ketone Supplements, such as Ketone Esters and Medium Chain Triglyceride Supplements (MCT Oil). Exogenous Ketones supposedly help you reach Ketosis faster, and enhance the benefits of Nutritional Ketosis, but we’ll explore the truth behind these claims.

Ketones in the Body

Breath Ketones


Ketones have a distinctive fruity smell, which can be detected on your breath (Keto Breath) when you enter Ketosis. Look positively on this bad breath, because it means you are making progress on your Keto Diet.

Measuring breath ketones is not easy to do at home, and getting an accurate reading of these ketone levels would require laboratory testing. However, there are other ways to test your Ketone levels at home.

Blood Ketones


Water-soluble Ketone Bodies are transported from your liver, through your body in your blood, where they provide the essential energy needed for life.


You can easily measure the ketone levels in your blood at home using simple handheld equipment similar (and sometimes the same) as the blood meters used by Diabetics. These Ketone Meters are readily available to purchase online.


Some Ketone Meters are easier to use than others and consumables can be expensive, as you’ll need lancets (to ‘prick’ for blood), as well as test strips.


The On Call GK Dual Ketone Pack will check for glucose levels as well as ketones. Others, like the (Amazon Choice) eBketone Blood Ketone Monitoring System, just test for ketones.



Monitoring your ketone levels in this way can give you an accurate pattern of your fasting ketone level - for instance when you wake up in the morning - or how you react after eating certain foods, which can help you establish things that spike your insulin levels and wreck your progress on your Keto Diet.


Testing the ketones in your blood can help you protect against slipping into Diabetic Ketoacidosis (DKA), and you should be sure to pay attention to ketone levels that are too high.

What should normal blood ketone levels be*?

  • Under 0.6 mmol/L – is a normal blood ketone value

  • 0.6 to 1.5 mmol/L – indicates that more ketones are being produced than normal

  • 1.6 to 3.0 mmol/L – a high level of ketones and could present a risk of Ketoacidosis

  • Above 3.0 mmol/L – a dangerous level of ketones, seek immediate medical care.

* from Diabetes.co.uk


Best Budget Ketone Meter for Home Ketone Blood Testing - Forever Keto

Ketones in Urine


Ketones are naturally flushed out of your body through urine, and can be monitored at home with Ketone testing strips. This simple to do test is best done first thing in the morning, or last thing at night to give the most accurate reading.


Using Ketone testing strips you’ll be able to check your ketone levels and know as soon as you are in Ketosis, but also keep an eye out for high levels, which can be a result of dehydration - a common side effect of a Keto Diet.


If you are following a Low Carb or Ketogenic Diet, it’s important to be aware of your ketone levels, as if they are low, it can be an indication that you are not in Ketosis. This can happen when you are not paying attention to what you are eating, or your portion size, and carb creep sets in, knocking you out of Ketosis.


Ketone Test Strips - Urine Test for Ketones - Forever Keto

Ketone Supplements



People following a Keto Diet may turn to Exogenous Ketone Supplements, either for assistance to reach nutritional Ketosis, or for performance enhancement.


However a word of caution here: If you are consuming Exogenous Ketones, you are taking in energy, so if your goal is weight loss, you may want to hold for a beat and consider if they are the best thing to help you reach your goal.


Ketone Esters are not readily available in the UK, and anyway they are prohibitively expensive. Further research is needed to prove the usefulness of Ketone Esters for weight loss, but they have been embraced by some athletes for their claimed performance enhancing capabilities.


In 2018 a new world record for one hour Velodrome Cycling was set by Vittoria Bussi, whilst she was taking a Ketone Ester Supplement. She is quoted as saying “The combination of mental lucidity and physical energy was strong and effective”


MCT Oil is probably the most commonly known ketone supplement, made hugely popular by Bulletproof Coffee. It’s not actually an Exogenous Ketone, although it has similar properties.

MCTs (Medium-Chain Triglycerides) are found in natural foods like coconut oil, palm kernel oil and butter. These oils can be converted into a supplement that you can add to your food or drinks as a replacement for other fats or oils. They're a great energy source for your body and in their purest form, it is claimed that they can help you burn fat