How to monitor blood ketone levels (the Right Way)

  Did you know ketosis and the ketogenic diet plan was first invented in the 1920's? Its original evolution within the health sphere saw many significant health benefits for previously untreatable epileptics. People with conditions unmanageable by medication suddenly found their symptoms improving because of a careful ketogenic change to their lifestyle. With a diet plan boasting countless great benefits, the ketosis revival is now in the making.

What is ketosis?

Adopting a ketogenic diet aims to initiate a metabolic state described as ketosis. Normally, with an un-altered diet plan, a person’s metabolism proceeds in a state of glycolysis i.e. it uses glucose found in the blood to supply the body with energy. However, when following a ketogenic diet, the body finds energy in a different form – from ketones, not from glucose.

This metabolic change is provoked by a switch in macronutrients. Whereas a normal western diet now has a very high amount of carbohydrates, a ketogenic diet restricts this macronutrient in preference for protein and fats.

The science backed benefits of ketosis

Such a simple change, such vast results. The benefits of a ketogenic diet are wide ranging – want to lose wait? Ketosis enables fat burn. Want to preferentially tackle stomach fat? Ketosis helps preferentially burn abdominal fat. Want to reduce future risk of heart disease? Ketosis helps keep hearts healthy.

The benefits of a ketogenic diet are not hearsay, they’re science backed;

  • Ketosis burns fat

A modern diet, rich in carbohydrates finds energy in blood sugar, a process known as glycolysis. When blood sugar levels rise, insulin is released helping curb levels back to normal. Diets rich in carbohydrates, especially simple carbohydrates (white rice, white potatoes, white bread) cause frequent blood-sugar spikes and therefore frequently provoke insulin release.

Insulin is a hormone that promotes the storage of body fat, therefore blocking fat-burn.

On the other hand, reaching a state of ketosis has the opposite effect. Ketosis is sometimes described as ‘starvation mode’ – the body enters it when running low on blood-sugar energy. This imitation of starvation provokes the body to cling on to remaining sugar reserves, instead burning fat as an alternative energy source (ref).

  • Ketosis prevents pangs of hunger

Painful stomach cramps make low-fat dieting difficult, thankfully a ketogenic lifestyle has no such side-effects. Diets high in low-fat often tend to be high in refined carbohydrates – foods that are quickly digested and broken down into blood sugars. Quick alterations in blood sugar lead to spikes and troughs. Spikes of quick release energy followed by troughs of post-sugar slumps. When the body lacks energy as in the spike and trough model it requires frequent energy top-ups leading to the dreaded hunger pangs.

However, a ketogenic diet low in carbohydrates and high in fat slows digestion, evening blood-sugar levels and attenuating the blood-sugar peak and trough model.

Studies show when low fat and ketogenic diets are trialled in parallel, ketogenic diet followers boast significantly fewer stomach problems alongside significantly less hunger (ref).

  • Reduction of belly fat

It is clear western diets promote storage of belly fat. When it comes to fat, not all fats are created equal. Subcutaneous fat is stored body-wide, under outer layers of skin. The ‘pinch an inch’ concept of body-fat measurement, notes the amount of subcutaneous fat. However, there’s also visceral fat to consider, a type of fat often being the more worrying of the two. Visceral fat, as opposed to subcutaneous fat, surrounds the vital organs and is linked to inflammation, heart disease, diabetes and metabolic dysfunction (ref). Ketogenic diets have been show to preferentially reduce visceral fats stored around the belly area (ref).

  • Ketosis helps to reduce the risk of heart disease

Low carbohydrate diets such as the balance found in ketosis driving diets may help reduce heart disease risk because of two changes to body chemistry;

  1. Reduction of blood triglycerides
  2. Increased levels of good cholesterol (high density lipoprotein – HDL)

Triglycerides are a type of fat that can be dissolved into blood and transported and stored for energy. High triglyceride levels are linked to an increased risk of heart disease (ref). Counter intuitively, it’s raised consumption of carbohydrates that causes a raised increase in blood triglyceride levels (ref). When dietary carbohydrate prevalence is replaced with a ketogenic diet high in protein and high in fat – blood triglyceride levels fall (ref).

Cholesterol comes in two forms – low density and high density. High levels of low density cholesterol (LDL) are associated with increased risk of heart attack (ref) therefore earning it the nickname of bad cholesterol. High levels of high density cholesterol (HDL) are associated with a lower risk of heart disease (ref) therefore earning it the nickname of good cholesterol. Increasing consumption of fats, as in the ketogenic diet, increases prevalence of HDL (ref).

  • Management of type 2 Diabetes

Eating a diet high in quick release carbohydrates requires increasingly greater amounts of insulin. A hormone that allows the sugars carbohydrates are broken down into, to be harvested from the blood stream and stored within cells for energy release at a later date.

Without the release of insulin, blood sugar levels remain high and hyperglycaemia sets in. Hyperglycaemia is a toxic state causing kidney damage, heart damage, brain damage and more.

Type 2 diabetes is a condition of insulin resistance, the body has been required to release insulin at such large levels for so long, that it’s biochemical processes have built a blindness to it. Like drug over-use, more and more is required to do the exact same job.

Switching to a ketogenic diet reduces the need for insulin as the body is switching from creating blood sugar from carbohydrates to creating ketones from fat. By following a low carbohydrate diet such as the ketogenic diet, sufferers of type 2 diabetes are able to reduce and even eliminate their need for medication (ref).

The rules of ketosis

With all these benefits to boast – how exactly do you follow a ketogenic diet? How do you ensure your body is hitting ketosis? How do you effectively burn fat rather than sugar? The answer? Careful manipulation of the 3 macronutrient groups; carbohydrates, proteins and fats.

Western diets are high in carbohydrates, high to moderate in fats and moderate to low in fats.

Ketogenic diets are high in fat, moderate in protein and low in carbohydrates.

But the science of ketosis goes much more deeply than this. Simply following a low carbohydrate diet may not be enough to push a person’s metabolism into ketosis. Instead there are figures to follow – ketosis is most often attained by following a 4:1 keto diet. For every 4 grams of fat eaten, 1 gram of protein may be eaten and carbohydrates should be kept to an absolute minimum – usually 20 grams or fewer per day.

Even still, knowing if your body is in ketosis can be difficult – that is, unless you have metrics to work with. If you’re wanting to know how to tell when your body’s in ketosis? How to tell if your body’s burning fat or how to monitor a ketogenic diet? You need to understand how to monitor ketosis biochemistry.

How to monitor ketosis

When metabolism is switched from sugar energy to ketone energy – body biochemistry changes. Aptly this switch reduces sugar levels and increases ketone levels. Metabolic ketones come predominately in 3 forms;

  1. Acetone
  2. Beta-hydroxybutyrate
  3. Acetoacetate

All 3 forms of ketone can be accurately measured from a person’s blood, breath or urine (ref). Making knowing whether a ketosis state has been activated simple and easy.

Ketosis can be monitored by;

  • Acetone levels in a person’s breath
  • Beta-hydroxybutyrate levels in blood samples
  • Acetoacetate levels in urine

Each method of measurement has varying degrees of accuracy, cost and reliability – with at home measurement being available for all 3 types of ketone.

How to choose a great ketone monitor

Relatively small levels of ketones, push the human body into a state of ketosis, meaning an effective ketone monitor should be of good quality, reliable, consistent and accurate. How do you tell? Which type of ketone monitor should you invest in? Do you want the ability to monitor ketone levels on-the-go or is sole at home use suitable?

While you may not yet have pondered these questions – we have answers that will make choosing the most appropriate ketone monitor for your lifestyle, simple.

Ketone urine monitors

The first of 3 ketone monitors categories, ketosis urine monitors aren’t fancy, but they are straight forward, relatively cheap and great for monitoring ketosis when first beginning a ketogenic diet.

Cost; $

Useably; Simple and quick

Reliability; Best when initially beginning a ketogenic diet, less reliable the longer a ketogenic diet is followed as urinary ketones lessen due to adaptation.

Accuracy; Low to Moderate - quantified qualitatively (with colour) rather than quantitatively (with numbers) – monitors excreted ketones rather than real-time ketone levels e.g. blood ketone monitors.

  1. Care Check Ketone Test Strips

These easy to use ketone urine dip sticks boast lab accurate results in a matter of seconds – they’re also FDA approved. Take a small amount of urine into a clean cup, dip the end of the ketone test strip in and wait a few seconds for the colour to develop. No change means you haven’t yet reached ketosis (if you’re just beginning a ketogenic diet), a pale purple colour shows initiation and the darker purple ranges indicate full-blown ketosis. The darker the colour, the higher amount of acetoacetate in your urine.

On the go? Although not recommended by the manufacturer if you want to monitor urine ketone levels away from home, you may urinate onto them directly.

  1. Bayer Healthcare-Diabetes Care Ketostix Strips 2881

Where some may find the lighter scale of the Care Check Ketone Test Strips harder to read, the Bayer ketosis strips unmistakably dictates ketosis with a fuller colour range, progressing past purple to deep-dark burgundy.

  1. Smackfat Ketone Strips

Another light pink to deep burgundy scale making ketosis analysis even simpler and quicker. These strips are kinder on the wallet than the Bayer Healthcare-Diabetes Care Ketostix Strips 2881 and the general consensus - they work just as well.

Ketone breath monitors

Easy and convenient ketosis breath monitors measure exhaled acetone levels, a relatively small molecule that is able to move from blood into lung air. This time around ketone levels are measured quantitatively rather than qualitatively i.e. you get a numerical reading rather than a somewhat subjective colour change. Ketone breath monitors measure acetone levels in nanomoles – this is many degrees smaller than the readings output by blood monitors which read in milimoles – we will discuss this in depth soon.

For ketone breath measurements, readings between 150-400nmol/L show the initiation of ketosis with levels from 400-930 nmol/L showing probable ketosis and readings in excess of 930nmol/L most stringently confirming ketosis.

Cost; $$$ initially, however no re-investment needed after initial purchase.

Useably; Very simple and quick with ketosis levels trackable electronically.

Reliability; Unlike urine strips which become less accurate the longer a ketogenic diet is followed, breath monitors remain reliable.

Accuracy; Low - moderate – breath monitors are the least accurate ketosis monitors in early stages of a ketogenic diet. For reliable, consistent accuracy see ketosis blood analysers.

Ketonix Breath Ketone Analyse

When it comes to breath monitors designed specifically for ketosis tracking – ketonix have the market currently cornered. This initially expensive device needs only to be exhaled into for 10 to 20 seconds for a ketosis result of yes, maybe or no. Blue, green, yellow and red lights highlight the varying levels of ketosis, with yellow being a potential state of ketosis and red being a definitely probable state of ketosis.

The device is portable, re-chargeable and technologically current – the ketonix breath ketone analyser is also able to track previous readings making ongoing analysis and past comparison simple and easy.

On the other hand, it’s worth noting that exhaled ketone levels do not always correlate with blood ketone levels. As migration of ketones from blood to breath is required for a ketosis breath monitor to work – levels read may not be real-time or as accurate as a ketosis blood monitor. Breath readings may also be effected by other factors such as alcohol consumption.

Overall a likely option to give a ketosis yes or no, however the numerical readings may be less helpful due to accuracy concerns.

Ketone blood monitors


The presence of ketones in blood is measured at a millimolar level – which is relatively dilute, however when compared to breath monitors, relatively much more significant. The reason – ketones need not migrate from blood to breath, or blood to urine, which is one of the many reasons why ketosis blood monitors are considered the most reliable. When ketosis is activated, blood ketones will be present at a range of 1.0 to 3.0 mmol/L.

Cost; $$-$$$ device is relatively cheap, however ketone monitoring strips are pricy and cannot be reused.

Useably; Can be painful, less on-the-go more at home monitoring

Reliability; Extremely reliable

Accuracy; High

Precision Xtra Blood Ketone Testing Kit

Picture of the box of Abbott's Precision Xtra blood ketone monitor
Picture of the box of Abbott's Precision Xtra blood ketone monitor

Blood ketone monitoring promises results in seconds. Simply insert a new test stipe into the meter, use the supplied lancing tool to prick a finger and touch the blood droplet alongside the strip ensuring the strip’s channel becomes full. Only a very small amount of blood is needed to fill the strip. Afterwards the meter returns a very accurate measurement of blood ketones as a numerical and trackable value.

Gluco RX HCT & Ketone Blood Glucose Monitoring System

Although specifically designed for type 1 diabetics, the Gluco Rx HCT & Ketone monitor will work just as well for tracking blood ketone levels. The Gluco Rx monitor tracks 3 parameters for enhanced accuracy – self adjusting based on the combination of readings taken. Although you will be most interested in the ketone levels, the device also reads for blood glucose and haematocrit (ratio of red blood cells). After filling the ketone strip channel with blood, the ketone blood monitor returns a reading in fewer than 10 seconds.

How to read ketone monitor results

In the early stages of a ketogenic diet, it’s best to take a ketone reading every day to understand how dietary intake effects your blood ketone levels. Every individual is slightly different so monitoring this period closely helps understand exactly how your body reacts.

Once reaching fairly stable ketogenic readings, you may reduce monitoring to a weekly time window.

Practical steps for making ketosis work for you

Initially a ketogenic diet requires a large overhaul of your approach to eating. Culling of carbohydrates can be tough and achieving a state of ketosis can sometimes feel elusive. Pushing into this state, does not always have to be about increasing your keto-ratio, there are other helpful nutrition and lifestyle changes which help make achieving and maintaining ketosis a smoother process;

  • Increase your amount of medium chain triglycerides (MCTs)

MCTs are naturally found in coconut oil at around 60%, they are a type of triglyceride or fat, which is very efficiently metabolized, meaning it is easily digested and absorbed. MCT oil can be purchased as a pre-concentrated product and may help achieve a deeper state of ketosis without having to adjust to a higher keto ratio.

  • Count your carbohydrates closely

When beginning a ketogenic diet it is very helpful to keep a beady eye on the carbohydrate count of foods. Although timely at first, the carbohydrate counts of foods are quickly learnt. Achieving ketosis is most possible when keeping carbohydrates to 20 grams per day; 20-23 grams is the haloed window, however depending on whether you exercise 20-30 grams may also be sustainable.

  • Ensure meals are regularly spaced

When aiming for a ketogenic state, it’s best to eat every 4 hours to help deactivate glycolysis and remain in ketosis. If while tracking the effects of a ketogenic diet, you see ketone levels falling during certain time periods, integrate a fat rich snack in advance of this time. Alternatively you may want to consider splitting meals into 2 portions instead of adding additional snacks into your routine.

  • Read restaurant menus before you visit

The biggest temptation of all appears when eating out. Restaurant menus are designed to tingle your taste buds and meals can often contain hidden carbohydrates. Read the menu before visiting and make a note to ask for salad dressings and garnishes to be ‘on-the-side’. Fish and vegetable based meals are a great option.

  • Exercise to aid removal of glycogen stores

Naturally the human body prefers blood-glucose as an energy source, so practises which make the presence of glycogen scarce help to push the body towards ketosis. Exercise is very efficient at using up glycogen stores (ref). If trying to enter or maintain ketosis, it may be work scheduling exercise for time periods directly after allowed carbohydrate intake. If you’ve surpassed your carbohydrate intake and want to compensate, exercise is a great option.