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Testing for Ketosis

There are more and more self-tests on the market that claim to tell you whether you are in ketosis or not. These include breath tests, urine strips, and blood testers. It may sound like a convenient tool to measure if you’re on the right track, right? However, many tests are not accurate, and it can be a waste of your money. Moreover, it can be demotivating if the test indicates that you are not in ketosis when you are being careful about your diet.

Urine Test Strips

Let’s start with the most commonly used keto testers, the urine strips. The idea behind them is similar to a pregnancy test, but instead of measuring the pregnancy hormone, these strips measure the amount of ketones in your urine. The color of the strip is supposed to indicate how deep you are in ketosis. These tests are highly unreliable in determining whether you are actually in ketosis. What the test measures is the amount of ketones present in your urine. This tells you nothing about the number of ketones in your body. The ketones in your urine are the ones your body has produced but does not need, so they are excreted.

How Ketones Work

In simple terms, when you eat very few carbohydrates, your body starts producing ketones to replace the role of sugars. Ketones ensure that your brain functions optimally and that all processes in your body run smoothly. However, your body needs some time to adjust to this. When you start a ketogenic diet, your body goes into overdrive, producing more ketones than necessary. The body does this to ensure your well-being. Any excess ketones that your body doesn’t use are excreted in your urine, and that’s what the test measures.

Darker Color Doesn’t Mean Better

Many people believe that the darker the color on the test strip, the deeper they are in ketosis and the better they are doing. This is not true. A darker color simply indicates that your body has produced far more ketones than it actually needs, resulting in more being excreted and thus being measured by the test.

Your Body Will Fine-Tune

As you continue on a ketogenic diet, your body will fine-tune itself based on your diet and needs. Your body is constantly optimizing everything happening inside it, including the amount of ketones it requires, which is monitored by your brain. Your body dislikes wasting energy, so once it becomes accustomed to a ketogenic diet, it won’t overproduce ketones. Instead, it will only produce what it needs. Consequently, over time, you will excrete fewer ketones in your urine because the ketones you produce are being utilized and are not considered “waste.”

The Test Strip Can’t Measure Anymore

Because you’re no longer producing large amounts of extra ketones, the test can’t detect or can detect very few ketones in your urine because there are almost none left to measure. As a result, the test may incorrectly indicate that you are not in ketosis. However, if you have been strictly following a ketogenic diet and adhering to your macros (fat/protein/carbohydrate ratios), you are likely in ketosis.

Breath Meter

Another way to test if you are in ketosis is by using a breath test. This method is similar to a breathalyzer test that you might have to take with the police to determine alcohol consumption. However, these tests are also not entirely reliable. It’s no coincidence that sometimes you have to go to the police station for a blood test to get a more accurate result. The same applies to breath testers for ketosis.

The same arguments about how ketones work, as mentioned earlier with urine testers, apply here as well. The number of ketones in your breath is related to the ketones produced unnecessarily. In other words, if you have been in ketosis for a while, the test is likely to indicate that no ketones could be detected, suggesting you are not in ketosis. A well-known phenomenon when you start a ketogenic diet is bad breath and an unpleasant taste in your mouth. As you continue on a ketogenic diet, this goes away because your body starts producing the right amount of ketones.

Blood Test

A blood test is the most reliable way to determine if you are in ketosis. However, it is also the most expensive method, and some people may find it uncomfortable to prick their finger for the test.

Ketones are transported through your blood to the right cells in your body. The ketones measured in your blood are still needed for use and are not in excess. Therefore, this is the most reliable way to test if you are truly in ketosis.

Is It Worth the Money?

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Urine testers and breath testers, in my opinion, are a real waste of your money and, moreover, a significant risk to your motivation and well-being. Why would you want to spend money on something that is not reliable? Blood testers provide a more reliable answer, but they are more expensive to use, and you have to prick your finger.

Is it really important?

Before you decide to spend a lot of money on testers, ask yourself, “Is it really important to you, and if so, why?”
Medical indication: If you have a medical reason to follow a ketogenic diet, I can personally see the value in why you might want to measure it. You can fine-tune more effectively and actively improve your health. There are, of course, other ways to see differences as well. For example, if you have diabetes, you can quickly see it in your blood glucose levels and in the amount of medication you may have already reduced.

Without a medical indication: If you don’t have a medical reason to follow a ketogenic diet but are doing it because you want to lose weight, have more energy, feel better, etc., then it’s worth asking yourself how important it is for you to be able to measure whether you’re in a state of ketosis. Before you spend money unnecessarily, take a good look at how you feel, how well your clothes fit, or what the scale or tape measure shows. What is more important to you, knowing through a test that you’re in ketosis or noticing a difference as you get closer to your goal?

What if you don’t notice a difference…

Most people who transition from a high-carb diet to a ketogenic lifestyle notice the first signs of ketosis within a day. You might notice it in your mouth (a metallic taste, dry mouth, bad breath), you’ll probably feel a bit more energetic (less lethargic), and you might experience symptoms of the keto flu, and perhaps you’ve even lost some weight in the first few days.
However, there are times when you may not notice any differences even though you’re strictly following a ketogenic diet. This can be frustrating, especially when you’re putting in a lot of effort. In such cases, testing can be helpful for your motivation, but make sure to choose the most reliable form of testing, or it won’t be of much use…

You can also choose not to test at all. Take a critical look at what you eat in a day. It’s possible that you may not be doing as well as you think, especially if you’re new to ketogenic eating. If you’re unsure, don’t hesitate to ask for help and advice. There’s nothing to be ashamed of. Our Facebook group is always willing to assist you. You can post what you typically eat in a day and ask if people can take a look and offer advice for adjustments.

Every body is different, and sometimes it takes time… Most people notice fairly quickly (without testing) whether they are in ketosis, but it doesn’t always have to be that way. It’s true that every body is unique, and it can even happen that you don’t notice any difference in the first 6 to 8 weeks, but a lot is happening in your body during that time. A friend of mine didn’t notice any difference in the first two months, even though she was strictly following a ketogenic diet. She didn’t lose a single gram, and she didn’t feel any different. But then suddenly, something clicked. She became more energetic, and the excess weight started to disappear. Sometimes you have to give your body time to adapt and adjust. So, don’t give up after a few weeks, but do take a closer look at whether you’re making the right choices in terms of your food.


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