This blog post is an accompaniment to the book ‘Master your Weight Loss’ found here.

I left this section out of the book as I wanted the book to be a simple guide to the ketogenic diet. From experience of taking clients through this dietary approach, most are not interested to measure their levels of ketones. This is partly due to not wanting the financial outlay. And many get a good result without the need to test. However, sometimes just following your interpretation of the diet does not mean you’ll necessarily get into ketosis.

If your goal is to get into ketosis, you won’t know unless you test.

What Does it Mean to Be In Ketosis?
When carbohydrates are restricted on the ketogenic diet, your body is forced from burning mainly glucose to using fat primarily as fuel. To satisfy organs such as the brain which cannot burn fat the liver produces ketones. Ketones are made from fat and used as an alternative fuel source. Ketosis means you are burning fat for energy and is a perfectly natural state to be in.
Note: Nutritional ketosis is not the same as ketoacidosis which is a dangerous condition for a type 1 diabetic to be in (1).

Does it Matter if I’m in Ketosis or Not?
if your goal is weight loss then being in ketosis is an optimal place to be. The reason for this is, you’re able to access body fat for fuel, are more likely to find your hunger and cravings suppressed/manageable and experience good energy levels.

Any diet where you are fighting hunger, cravings and your energy levels are poor will become an intolerably difficult, if impossible diet to stick too.

How Do you Test for Ketones?
There are 4 ways you can measure ketones: I’ve kept this article as simplistic as possible rather than go into great detail about different ketone bodies. If you want to delve deeper into this subject a good book is The Art and Science of Low-Carbohydrate Living – by Volek PhD, RD, Jeff S. and Phinney MD, PhD, Stephen D.

In basic terms there are 3 ketone bodies (2):
• Beta-hydroxybutyric acid – measured using a blood meter
• Acetoacetic acid – found in the urine
• Acetone – is released in the breath

The ways to measure each are:
1) Using a blood ketone meter
The blood ketone meter accurately measures ketones. And is relatively easy to perform at home once you have the meter. It requires a skin prick using a lancer which usually comes with an all-in kit. The biggest issue with these kind of meters is the price of the test strips. These can vary in price depending on where you buy them from and the type of meter being used.

The precision Xtra by Abbott is a reliable meter, though I’ve not seen the strips as cheap as the Keya Smart meter.
The Keya Smart meter works out around £71p per strip once you take into account the postage of the strips.
Keya are also bringing out a new meter especially designed for those interested in nutritional ketosis.

Their website is
When measuring blood ketones, the range for nutritional ketosis is 1.0 – 3.0 millimolar.


2) Breath analysis
If you are not willing to spend out on a blood meter with the recurring fee of the strips then a ketone breath analyser might be for you. Once you have purchased a device you can keep reusing it without any additional cost.
One of the best-known ketone breath analyser is the Ketonix
The breath ketone analyser does not correlate to blood testing as they measure different ketone bodies (3). The breath analyser gives a good indication to whether you are burning fats for energy. If you get a low reading, you’re probably burning glucose for energy and a high reading indicates you are using fat for fuel.

Ketone breath readings can be skewed if you do not breathe into the analyser correctly every time, have recently; drunk alcohol, exercised, or even eaten a large amount of garlic (4).
The Ketonix uses a traffic light system of colours to show your level of ketosis.








Blue = no or very small trace of ketones
Green = small trace of ketones
Yellow = moderate trace of ketones
Red = high trace of ketones

The colours show on the device itself and also when you use the Ketonix software which displays an image resembling a rev counter. To use a breath analyser, you take a normal breath and then exhale into the meters mouthpiece, fully expelling all air from your lungs. This is important as the ketone concentration is in the last 15 seconds of air out your lungs. The needle on the rev counter will then show your level of ketosis.

If you want a cheaper option to the Ketonix you could investigate the Keto Detector v.2 on sale for $24.95

3) Urine Strips
This is the cheapest way to test ketones but is only effective during the first 1-2 months of your ketogenic journey. The reason being, as your body gets better used to using ketones less spill out into the urine. Therefore, if you initially had positive urine strips, then negative results 1 month later but your diet hadn’t changed, it could mean that you had become fat-adapted.
When you become fat-adapted your body has become efficient at using ketones for fuel. This is generally where you will find your energy levels pick up and you get the health benefits of the ketogenic diet.

In a fat-adapted state which ever method you choose to measure ketosis may show lower levels of ketones than when you start.

4) Your Own Analysis of your Bio feedback
If you are exceptionally in tune with your body or you have used some form of testing in the first month then you may have a good idea to whether you are in ketosis or not. Some people notice it in their breath which can smell of pear drops or find their taste becomes metallic or sweet. You can also use your bodies bio feedback to give you clues. If you experience little to no cravings, can go long periods without hunger and have good energy levels you may well be in ketosis.

I believe testing is important if you are not getting the results you want from trying the ketogenic diet yourself for at least 8 weeks.

1. Qiao Y, Gao Z, Liu Y, Liu Y, Cheng Y, Yu M, et al. Breath ketone testing: A new biomarker for diagnosis and therapeutic monitoring of diabetic ketosis. Biomed Res Int. 2014;2014.
2. Prabhakar A, Quach A, Zhang H, Terrera M, Jackemeyer D, Xian X, et al. Acetone as biomarker for ketosis buildup capability – a study in healthy individuals under combined high fat and starvation diets. Nutr J. 2015;14(1).
3. Ketonix. KETONIX® Reusable Ketone Breath Analyzer – Troubleshoot issues [Internet]. 2017 [cited 2017 Oct 21]. Available from:
4. Anderson JC. Measuring breath acetone for monitoring fat loss: Review. Obesity. 2015;23(12):2327–34.