- Measuring Ketosis: A Quick Guide to Ketone Strips
- What Are Ketones?
- What Are Ketone Strips?
- How Do They Work?
- Are Ketone Strips Accurate?
- Some Alternatives
- Do I Need to Test for Ketones?
- Bottom Line
- Ketones in Urine: All You Need to Know
- Ketosis and Ketone Metabolism Fundamentals
- Why You Should Test for Urine Ketones
- Ketosis vs. Diabetic Ketoacidosis
- How to Test for Urine Ketones
- Other Ways to Measure Ketones
- Is Urine Ketone Testing for You?
- How to tell if you’re in ketosis, from monitoring your bathroom patterns to testing your blood
- You have bad breath
- You need to go to the bathroom more
- You don’t have a lot of energy
- You feel like you have the flu
- You’re not very hungry
- You’re constipated
- You have trouble sleeping
- A keto stick (or blood glucose meter or breathalyzer) tells you you’re in ketosis
- How to read ketone strips
- Tired of peeing in to cups? Us too.
- The best keto strips, according to Amazon
- The Problem With Pee Strips
- The Best Keto Strips to Measure Ketosis
- How to test ketones
- Keto test strips
- Ketone test best practices
- What is Ketosis?
- What are Ketone Test Strips?
- What Level of Ketone Bodies is Best For Health?
- How Accurately Do Ketone Strips Measure Ketosis?
- What Are Some Other Ways To Measure Ketones?
- What is the Best Way To Measure Ketosis?
- Final Thoughts
- Restricting carbs means less glucose
- The state of ketosis: Finding an alternative source of energy
- How to detect ketosis
- Potential errors from testing for ketones in urine
- Keto diets don’t always result in weight loss
- The bottom line
- The best way to test ketones in blood, breath or urine
- 1. The three types of testing: blood, breath and urine
- 2. Accuracy
- 3. Price
- 4. Qualitative factors
- 5. Pros and cons
- 6. Conclusion
- How measuring ketosis can help
- How to measure ketones
- When to measure ketones
- Guideline targets
- Achieving ketosis
- Ketosis with type 1 diabetes
Measuring Ketosis: A Quick Guide to Ketone Strips
Ketone strips, also called keto strips and ketone test strips, are thin paper strips that detect ketones in urine. They’re cheap, convenient, and will give you results within one minute, tops. They do come with some drawbacks, however, which you definitely want to be aware of before making a purchase.
If you are curious as to why you need ketone strips in the first place, as well as how these products actually work and if there is any other way of testing for ketosis – then keep reading.
Our guide will also quickly go over the biochemistry of ketones and describe how your body uses and releases these compounds that so many keto dieters want more of.
What Are Ketones?
Ketones are water-soluble molecules that your liver makes in the absence of glucose. They include the following three:
The purpose of ketones is to provide the body with an alternative fuel source. On a standard high-carb diet, your body runs primarily on glucose (sugar). But when your body is starved of carbohydrates – like when you are on a ketogenic diet – it runs on fat and turns a portion of it into ketones.
Most cells in your body can use fat for energy, but your brain cannot. The brain needs ketones in order to survive when glucose is running low, and this is one reason why ketones exist. Another reason is because long-chain fatty acids cannot cross the blood-brain barrier .
When ketone levels start to rise, a simple test can detect them in the blood, breath, and urine. Ketone strips detect ketones in the urine. These test strips are the most popular and convenient way to test for ketosis, especially for keto dieters.
What Are Ketone Strips?
When on a ketogenic diet, your goal is to achieve ketosis – an altered metabolic state where the body burns fat instead of glucose for fuel. While in ketosis, your body also makes an abundance of ketones. “But how can I tell that I’m in ketosis?” you might ask. That’s where ketone strips come in handy.
When talking about ketone strips, what most people are referring to are paper test strips that test for ketones in urine. These products are available over the counter, in drugstores, and online. At Kiss My Keto, we also sell Ketone Urine Test Strips – 200 Count and at an affordable price at that.
Ketone strips were originally developed for people with type I diabetes who tend to be at a higher risk of ketoacidosis – a life-threatening condition where ketones reach dangerously high levels and make the blood acidic. In healthy people, however, the danger of ketoacidosis is extremely low, so there’s no need to for you to worry if you’re not diabetic.
If you are diabetic, however, keto test strips can be an easy way for you to monitor your health. Still, blood testing would be a more accurate way to do this. When doctors measure blood ketones, here is how they interpret the results :
- Below 0.5 mmol/L – normal
- Between 0.5-3 mmol/L – nutritional ketosis
- Over 3 mmol/L – high ketone levels
- Over 5 mmol/L – dangerously high and indicative of ketoacidosis
Keep in mind that the values used on ketone strips are different from the ones above. Most of the time, you’ll be looking for changes in color on the strip and comparing the results to a color chart that comes with the kit. Light pink means the level of ketones in your urine is low, while dark purple means the opposite (you’ll understand what we’re talking about in the next section).
How Do They Work?
Ketone urine-testing strips have an absorptive pad on one end. The pad contains a chemical reagent (usually nitroprusside) that changes color in the presence of acids such as ketones in urine . The color depth change varies depending on the concentration of ketones. Light pink means ketones are present but in small amounts. Dark purple means you’re in full-blown ketosis.
Most of the time, these tests detect acetone, and occasionally acetoacetic. The presence of both is a sure sign you are in ketosis. Beta-hydroxybutyrate, which is the most biologically active of the ketones, is largely present in blood and, unfortunately, kertone strips won’t detect it.
The way you use keto test strips is like this: you pee directly on the strip (on the part with the absorptive pad) or you immerse it in a urine sample. Then, you wait 15 seconds to a minute for the pad to change color. Compare the color to the color on the chart you received with the test kit, and voila, you know how many ketones are in your urine.
Are Ketone Strips Accurate?
Ketone strips are accurate when you’re just entering ketosis, that is in the first week or two of a ketogenic diet. This is the time when your body is still adapting to this diet. And in case you didn’t know, there is a difference between being in ketosis and being keto-adapted.
Ketosis is a metabolic state characterized by raised levels of ketone bodies; keto-adaptation is when your body is able to use these ketones for energy. More specifically, keto-adaptation is when your ketones start fueling your brain and fatty acids begin fueling your muscles.
After keto-adaptation, ketone strips may not be the most accurate way to measure ketone levels. The reason? Well, when your body makes more ketones than it can use, it gets rid of it through urine or breath. But when ketones are fully metabolized, few, if any, will appear in the urine.
What all this means is that ketone strips don’t always paint the full picture in terms of how many ketones are exactly in your system. On the bright side, ketone strips are cheap and you can use them when just starting a keto diet to see if your ketone levels are rising.
There are two more ways to test for ketones: with blood ketone meters and ketone breathalyzers. Both are more expensive than ketone urine test strips but also more accurate.
Blood ketone meters are the most expensive of the bunch. Not only does the actual meter cost $50-$100, but the test strips that go with it are also expensive.You do get the bang for your buck, however, as these tests detect beta-hydroxybutyrate – the most metabolically active of ketones.
Ketone breathalyzers, on the other hand, are cheaper but less accurate than ketone meters. These devices detect only acetone in the breath, but this doesn’t make them any less accurate. Studies show that breath acetone directly correlates with blood beta-hydroxybutyrate .
Another way to detect acetone in your breath is by smelling it. Acetone is a byproduct of beta-hydroxybutyrate and a highly volatile compound. When released through breath, it gives off a smell of nail polish that some also describe as “fruity”. If you’re noticing an unpleasant fruity breath lately – could be a sign of ketosis.
Do I Need to Test for Ketones?
In short, not really. Eating fewer than 50 grams of carbs per day is bound to put you into ketosis within a week or two. You can check for signs of ketosis like loss of appetite, weight loss, increased focus and energy, and a fruity breath.
But in case your curiosity is getting the best of you and you just need a sign that your body is making ketones, then try out ketone strips. You really have nothing to lose. Ketone strips are non-invasive, easy to use, cheap, and relatively accurate.
Make sure to test for ketones early in the morning or several hours after a meal. This will provide the most accurate results. Also, keep in mind that your hydration levels could affect your results. Researchers found that people with kidney problems may not get accurate results, so keep this handy fact in mind as well .
Ketone strips are an easy and affordable way to test for ketones in urine. They’re most accurate when used early in your keto diet. But you can use them at any time to see how things are going with your progress.
Ketone strips are most accurate in people without kidney problems and when used in the morning or after a meal. But don’t feel discouraged if no ketones get detected 2-3 weeks into your diet. This could simply mean that your body is using up all the ketones efficiently so none go to waste through urine.
If you want to test your ketones today, order our Ketone Urine Test Strips for just $7.64 for 200 strips. These strips are accurate and give results in as little as 15 seconds.
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Ketones in Urine: All You Need to Know
Years ago, those doing the low-carb, high-fat ketogenic diet represented a small subset of the population. Not anymore. The prevalence of people doing keto has increased exponentially; even your grandma might be saying, “I’m thinking of giving this keto thing a try.”
The increased popularity is for a good reason; several health conditions have been shown to benefit from a low-carb, high-fat lifestyle, including but not limited to neurological disorders, diabetes, polycystic ovary syndrome (PCOS), acne, and respiratory and cardiovascular disease risk.1
This has led to the creation of a variety of consumer products that can be used to measure ketones, which are produced by the body when someone practices carbohydrate or calorie restriction. Data nerds love this, and so do people who like to have concrete feedback about progress. Having something to measure and track is always great, and can help lead to compliance and better results.
If you are someone who is thinking about going keto, or interested in starting to measuring ketones (if you haven’t before), one way to do this is through urine test strips. Read on to learn everything you need to know about testing for ketones in the urine.
Ketosis and Ketone Metabolism Fundamentals
Ketosis is a physiological state that occurs when the body begins to rely on fat-sources for fuel instead of carbohydrates. This happens when carbohydrates are restricted and blood sugar falls, which might be achieved through a low-carbohydrate, high-fat ketogenic diet, fasting, and even prolonged exercise.
During ketosis, the ketone bodies beta-hydroxybutyrate (BHB) and acetoacetate (AcAc) are produced from fatty acids. Fatty acids are released from our internal stores when blood glucose is low. The circulating fatty acids then go to the liver for ketone production. Once these ketones are produced, they can be shuttled through the circulation to other tissues, where they’re taken up and metabolized for energy.
Usually, ketosis is defined as having blood ketone levels greater than 0.5 millimolar (mM). If you really want to know if you’re in ketosis, measuring your ketones is the way to do so.
Why You Should Test for Urine Ketones
Before going into the process of measuring for urine ketones, let’s discuss the reason why we are able to even measure urine ketones in the first place. Aren’t ketones present in the blood?
For the most part, yes.
Glucose, ketones, and other crucial nutrients like minerals are present at varying amounts in the blood. Eventually, blood (and the small-molecule passengers) will pass through the kidney—our body’s filtration system. In the kidney, small molecules are filtered into the urine, while others are reabsorbed back into the circulation.2 This process is important, especially when we are talking about ketones. This reabsorption process prevents what would essentially be a “waste” of energy. You can’t utilize ketones if they’re flushed down the toilet.
At low concentrations, most ketone bodies are reabsorbed by the kidney. However, when blood ketones begin to rise, some ketones (the ones not being utilized) begin getting filtered out. Thus, ketone bodies show up in the urine.
For this reason, if you’re on a keto diet or fasting (i.e. in a fat-burning state) and producing ketones, a simple urine test may provide a quick snapshot of your endogenous ketone production—a proxy for how much fat you’re using.3 That is, higher ketones mean more fat burning.
What about exogenous ketosis? Another way to get into ketosis is using exogenous ketone supplements. Does urine testing work for ketosis achieved this way?
It turns out, urine testing might not be ideal to test for ketosis achieved using ketone supplements, for a variety of reasons. We will discuss these later on.
Recipes with MCT oil
MCTs are rapidly converted into ketosis, thus helping you get into ketosis faster. Here’s the most delicious ways to incorporate them in your diet.
Who Should Test?
Anyone can use urine testing, but this method may be particularly useful for two types of individuals.
The group that comes most quickly to mind might be people on a ketogenic diet. And yes, urine test strips might be a great introduction to ketone testing for keto-dieters everywhere, with one caveat.
The reliability of urine tests strips is greatest during the initial phase of a ketogenic diet.
Keto-adaptation might have an influence on test results (read on to find out more about this). Anyone experimenting with fasting or trying to lose weight could also use urine test strips to get a reading on their ketosis level, and perhaps use them as a guide to plan an effective strategy.
Individuals with type I diabetes are sometimes advised to measure urine ketones as well. This might seem odd, but it’s a potentially crucial part of their disease management.
This is because people with type I diabetes can suffer from a condition known as diabetic ketoacidosis (DKA), where large amounts of ketones build up in the blood, causing it to become acidic.4 A positive urine test for ketones in someone with type 1 diabetes (T1D) might be a warning signal of DKA.
But if ketones are so “good”, why is DKA so harmful?
Ketosis vs. Diabetic Ketoacidosis
It’s crucial not to confuse these two terms, as keto diet “haters” and the media have occasionally (and incorrectly) done. Yes, both conditions involve high blood ketones, but their physiology and effects on the body are vastly different.
Physiological (nutritional) ketosis is harmless (beneficial, in fact). Physiological ketosis is the goal of any ketogenic diet or taking exogenous ketone supplements.
What defines ketosis exactly?
As mentioned, when blood BHB levels of >0.5mM are achieved, one is said to be in ketosis. Ketone levels can reach up to 7mM – 8 mM in some instances in healthy individuals.5 However, it seems like levels don’t get much higher than this (under normal conditions). The body’s feedback mechanisms involving several different hormones serve to regulate endogenous ketone production.6
The evidence is clear that physiological ketosis has substantial health benefits, maybe due to the fact that ketosis seems to activate certain “survival” pathways in living organisms. In fact, ketogenic diets have been associated with longevity (in mice).7,8
In addition, ketones are an efficient superfuel which have been shown to yield health benefits like weight loss, improved glucose control, better blood lipid profiles, mental clarity, and even improved athletic performances in some cases9,10,11,12 Long story short, humans seem to benefit from both endogenous and exogenous ketosis.
Diabetic ketoacidosis (DKA), on the other hand, is something to be avoided at all costs! Rather than beneficial, it’s a medical emergency.
DKA is an abnormal and potentially fatal metabolic condition, where not having enough insulin around (which type I diabetics don’t produce) leads to an inability to shuttle blood glucose into muscles and other body tissues for energy. This leads to high blood glucose levels,13 which, on one hand, can lead to fluid and electrolyte imbalances.
But, with low insulin (despite a high blood sugar level) also comes the metabolic signals that tell the liver to start using fatty acids to produce ketone bodies.
Normally, insulin inhibits this signal. High levels of ketones start to accumulate in the blood, often exceeding 20mM or higher, levels drastically above normal fasting levels.3 Ketones are mildly acidic, and this can cause the pH of the blood to drop, making blood more acidic. If not treated, this can be life-threatening, leading to coma and even death.14
Some signs of DKA include dry mouth, excessive thirst, frequent urination, fatigue, nausea, vomiting, abdominal pain, a racing heart beat, and rapid breathing.13
For type I diabetics, urine ketone testing can be invaluable. They’re often advised to measure urine ketones frequently in order to manage their condition. The American Diabetes Association (ADA) recommends testing for ketones if your blood glucose is over 300mg/dl, you feel nauseated, you’re sick or tired all of the time, you have a very dry mouth, or if your breath smells fruity or resembles nail polish remover and you feel confused or “in a fog.” These all may be signs of DKA. People with type 2 diabetes may also benefit from urine ketone testing.
How to Test for Urine Ketones
The ketones BHB, AcAc, and acetone can all be measured in various ways, depending on where each will be the most present. BHB is commonly measured using a blood test/meter, and acetone can be measured using a breath ketone meter.
AcAc is the ketone that is measured when you do a urine ketone test. This method won’t tell you (directly, at least) anything about blood BHB.
The process of urine testing for ketones is relatively straightforward. The first step involves purchasing urine test kit, which can be purchased over-the-counter from most drug stores or ordered online. After you have the test meter and urine test strips, all that is required is a few additional steps (to the bathroom).
To get a reading, pass the testing side of the strip through a urine stream, or dip the strip into a sample of urine and remove immediately. After 15 seconds, match the end of the test strip to the ketone color chart on the container.
Different brands of strips may differ in their exact color-coding, but generally a dark purple color is used to indicate the highest level of ketones. Test strips also have a color corresponding to a “negative” test—these results mean no ketones were detected.
It’s important to follow the 15-second rule. After this period of time, the color may continue to change further, leading to a result that doesn’t match up with reality.
When Should You Test?
The time of day you test might depend on what your goal is, or what you’re trying to see from the reading.
Studies have suggested that the reliability of urine ketone testing increases when the test is done in the early morning or in the late evening several hours after dinner.15,16 Wondering how they figured this out? Participants had to provide urine samples for a full 24-hours. Be happy you weren’t part of that study.
Whether you choose to measure at the suggested times or at a different point in your day, it’s probably best to pick a testing time and stick with it for consistency.
Advantages of Urine Ketone Testing
For the cost-conscious, urine testing is one of the cheapest ways to measure ketosis. Typically, a pack of 100 test strips can be purchased for around $10. Plus, urine test strips don’t require a fancy meter to read results—they’re displayed right on the strip.
Urine testing is also super convenient. For one, the strips can be easily purchased. Testing is quick, seamless, and can literally be done anywhere, at any time. And if the thought of sticking your finger multiple times a day makes you queasy, no need to fear. Urine ketone testing is non-invasive—no blood required! It’s a less expensive alternative to other methods of testing ketones.
Disadvantages of Urine Ketone Testing
Something not provided by urine ketone testing? Concrete numbers.
If you like hard data end-points to measure ketosis, urine testing might not be for you. Rather than a concrete number, urine strips give only a semi-quantitative measure of blood ketones, with colors on the strip corresponding to “trace,” “moderate,” and “large” amounts of ketones. Therefore, the test is somewhat subjective.
Many external factors can influence your urine ketone reading, and these could provide a reading higher or lower than what your actual ketone levels might be.
For instance, hydration can influence readings. If you’re under-hydrated, ketones might read high, and vice-versa for someone who’s “over-hydrated.” Certain medications and vitamins (in particular vitamin C) can also skew the results.3
Urine testing may also be a poor way to measure ketosis achieved exogenously. Here’s why.
Exogenous ketone esters (such as monoesters containing the ketone body BHB) will result in rapid, high ketone levels, equivalent to a multi-day fast or weeks of ketogenic dieting.17 But since we’re testing urine, those rapid increases in blood ketone levels won’t show up in the urine tests.
Most are used for energy, and the pattern of metabolism is quite different from that of endogenous ketone production. Only a small amount of exogenous ketones are excreted.17 It has also been shown that at higher blood ketone levels, urinary ketones no longer correlate with blood BHB.18
As we will discuss later, urinary ketone testing might become less accurate over time, such as if you consistently follow a ketogenic diet for many weeks or months.
Urine Testing and Keto Adaptation
Maybe you’ve been using urine test strips for a significant amount of time to measure the success of your ketogenic diet, and now begin to notice a change in your results, despite your habits staying relatively the same. Don’t blame the strips.
In this case, your metabolism has just changed, something reflected in the strips. When you initially start a low-carbohydrate diet, you’re teaching the body to rely on fat-based fuel sources rather than carbohydrates, which most of us have been using as our primary energy sources for our entire lives.
This necessitates an adaptation period (which can sometimes lead to the “keto flu”), and so for the first few days or weeks of a ketogenic diet, you won’t be great at efficiently producing or utilizing ketones for energy. Despite producing some ketones, you aren’t quite yet a proficient “fat burner.”
This is why ketones will appear in the urine. Since they all aren’t being used, they’re filtered into the urine, rather than being reabsorbed or utilized.
But, after some time on a ketogenic diet, keto adaptation will occur—you’re now more capable of producing and using ketones. At this point, it is possible that a larger amount of ketones are reabsorbed and used for energy, and less will appear in the urine.19 One study indicated that during fasting, the amount of AcAc and BHB increased exponentially as the fast grew longer.19 The same study indicated that there exists no maximal transport rate in the kidney for AcAC during physiological ketosis. That is, our ability to reabsorb ketone bodies might have “no limit.” Furthermore, the increased reabsorption of ketones was shown to minimize the loss of body protein during starvation. Although this study didn’t use people in a keto diet, the same concept might hold true. This is definitely a beneficial adaptation during periods of starvation, since during an actual food shortage, the body would need to conserve more ketone bodies and we might see the same thing in those adhering to a keto diet.
As you become more keto adapted, skeletal muscle actually starts to oxidize fatty acids directly. This then leaves more ketones available for our big juicy brains, and other organs that can’t use fats20,21 This means that someone who is better at using ketones will get a lower result on a urine ketone test than they should, maybe even a negative result. Where blood testing might give a high ketone reading, urine test strips might tell another story.
In summary, over time, urine testing becomes less accurate than blood ketone testing.
Quick Tips for Urine Ketone Testing
If you want to improve the accuracy and reliability of your results, there are a few key tips you should follow if you plan to use urine ketone test strips.
Most obvious is that you should consistently check and stay up-to-date on the expiration date on the urine test strips you’ve purchased. Typically, test strips will expire within six months of opening the bottle. Don’t use your urine test strips if the date on the bottle has passed.
Storage is important too. Make sure that you store test strips with the lid closed tight, and keep the bottle in a cool, dry place. Any excess heat or moisture can influence the strips and the chemicals they contain. Do not store in the refrigerator, and protect them from direct sunlight and heat.
Don’t remove the desiccant in the bottle—that’s the tiny white packet. The desiccant holds something called silica gel, which absorbs and holds water vapor, limiting moisture that could potentially ruin the urine test strips.
During testing, make sure you aren’t overly hydrated, and similarly make sure you aren’t dehydrated, as each could skew the test results. This is why early morning testing makes the most sense. Otherwise, test at the same time of day in order to control for outside influences that might affect urine ketone readings.
Last but not least, keep your hands away from the test strip material. Along with the above tips, this will improve the consistency of your results.
Other Ways to Measure Ketones
Urine testing for ketones isn’t the only way to measure your level of ketosis.
The first way involves measuring blood BHB. As the name suggests, this test will give you a reading of how much beta-hydroxybutyrate is in your blood.
This test involves using a BHB meter, and provides the most accurate ketone measurement available (that can be purchased by consumers directly).
For this test, you’ll need test strips along with a BHB meter and a lancet device to prick your finger. You should also probably have some alcohol swabs around to clean the area before pricking your finger and after you have gotten your blood sample. Get a drop of blood, place it on the strip, and feed the strip into the meter.
Advantages of blood testing include the accuracy of measurement. Blood testing also gives you a quantitative reading of BHB (in millimolar; mM).
Disadvantages of blood testing include the need to purchase a device and the strips, which can get costly. The test is also more invasive, requiring a fingerstick to get the drop of blood. This could become bothersome to some people.
The final measurement involves breath testing for acetone. This test device is a newer type of consumer product that measures the amount of acetone excreted in the breath. This involves the one-time purchase of a ketone breath meter from one of several companies that have made these devices available.
Advantages? You only need to purchase one device, and no strips are required.
Disadvantages of this method are that you need a larger handheld device that’s not as convenient as urine test strips. Breath meters are also less accurate than blood or urine testing, and only measure acetone, rather than the two ketones most prominent in the circulation: AcAc and BHB.
Very few studies have been done to validate breath meters or confirm their accuracy. This area of ketone testing is in its early stages.
Is Urine Ketone Testing for You?
Whether or not you opt to use urine test strips will depend on your goals: What do you want to actually measure? How long have you been on a ketogenic diet?
While it’s a quick, convenient, and low-cost option for ketone measurement, it’s also less accurate and far less numerical than other testing methods. Another caveat is that those on a long term ketogenic diet may find less and less utility from urine ketone testing as time goes on.
Urine test strips are probably great if you’re new to a ketogenic diet and want to test if your diet is actually working. Are the foods you’re eating actually getting you into ketosis? Urine strips might help you find out.
But, if you’re a “keto pro,” blood BHB testing might be the best method for you. This is also the case if you’re experimenting with exogenous ketones, which can be more accurately measured by blood testing.
Overall, urine ketone testing gives a quick, practical, and somewhat effective snapshot of ketosis. It’s up to you to decide if this method is adequate for your lifestyle.
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How to tell if you’re in ketosis, from monitoring your bathroom patterns to testing your blood
- Ketosis is a state in which your body uses fat, rather than carbs, for fuel.
- It’s not always obvious if you’re in ketosis or not, but some symptoms can indicate that you are.
- Certain tests can give you a better idea if you’re in ketosis.
- Visit INSIDER’s homepage for more stories.
The whole point of the keto diet is to achieve ketosis, or that glorified mode in which your body burns fat, rather than carbs, for energy. But if you think you’re in ketosis when you’re not, or think you’re not when you are, you can come up short on your goals.
Fortunately for people determined to follow the plan (which, by the way, many health experts don’t recommend), there are some signals that can indicate you’ve entered ketosis. There are also tools you can use to determine if you’re in ketosis or not.
Here, registered dietitians explain what to look out for if your goal is ketosis.
You have bad breath
During ketosis, you’ll pee out ketones, or chemicals your liver makes from fat to fuel your muscles and other tissues, according to WebMD. You can also smell ketones on your breath, said registered dietitian Penny Scholl, who’s maintained a 120-pound weight loss on a low-carb plan.
Scholl said your breath may take on a noticeable fruity smell, while other people say it makes their breath smell like nail polish remover.
You need to go to the bathroom more
When you begin restricting carbs, your kidneys switch from retaining salt to excreting it, Scholl said. When this occurs, people notice that they take more frequent trips to the bathroom to pee.
Read more: 10 of the biggest downsides of the keto diet
You don’t have a lot of energy
The body does not immediately switch from using glucose to ketones for fuel, Scholl explained. As you transition, you’ll likely feel sluggish.
You feel like you have the flu
The “keto flu” describes symptoms including headaches, irritability, difficulty sleeping, and weakness, Scholl said. Part of this is due to the body switching over to a new energy source, she explained, and some of it is due to the loss of sodium and other electrolytes due to frequent urination.
Often, these symptoms can be reduced by staying hydrated and replacing electrolytes by adding a bit of salt to your food, she said. The symptoms should also decline with time, said Ohio-based registered dietitian with Abbott Pam Nisevich Bede. “Research shows that most people can achieve ketosis in less than a week after implementing dietary changes, but a full adjustment to the keto diet usually takes three to five weeks, if strictly adhered,” she said.
You’re not very hungry
Many people find that they are not as hungry on the keto diet as they used to be, Scholl said. “This is thought to be due to the suppression of hunger-related hormones such as ghrelin,” which stimulates appetite, she explained.
“Cutting out vital fiber sources from grains and fruits can disturb digestion and the microbiome in your body,” said Miami-based registered dietitian Monica Auslander Moreno. One result is constipation, though you can also experience vitamin and mineral deficiencies and possibly put yourself at risk for certain diseases.
You have trouble sleeping
“Ketosis can cause disturbed sleep” because the body is physically in a state of starvation, which messes with sleep, Auslander Moreno said. Without many carbs, too, the body can experience dips in certain sleep-promoting hormones, though long-term, the keto diet may improve sleep, according to an earlier INSIDER story.
A keto stick (or blood glucose meter or breathalyzer) tells you you’re in ketosis
“One of the best ways to determine if you are in ketosis is by using keto sticks,” Scholl said. There’s usually a color key included on the bottle of keto sticks, which will show you the level of ketones in your urine. If you are excreting ketones, then you are probably in ketosis.
For an even more accurate test, ask your doctor to take a blood sample to test serum blood ketones, suggested New York City-based registered dietitian Abigail Rapaport. Alternatively, you can purchase a blood glucose meter specifically designed to test ketones. However, keep in mind that these tests are more invasive than urine sticks, since you need to prick your finger, Rapaport said.
A breathalyzer that monitors acetone, a byproduct of ketosis, is another option to consider, Rapaport said. Still, breathalyzers may not be as accurate as blood ketone meters and they tend to be more expensive than ketone urine strips, she said.
How to read ketone strips
But first, what is a ketone strip exactly?
A ketone strip, also known as keto strips or ketone tests strips, are comprised of thin plastic strips with a small reactive pad at the end that detects ketone presence in urine.
Being in ketosis or following a low-carb diet for an extended period of time causes a measurable increase of ketones in blood and urine. Keto strips are a low commitment way to start testing the waters with the keto or atkins diet. Read on to learn how to read ketone strips easily and effectively!
- Learn about the keto diet if you want measurable results
Most healthy people will not have significant levels of ketones in their body if they’re not following the diet. Read our ketogenic diet guide to learn more about keto so you can achieve ketosis, faster.
- Pee in to a cup (or have great aim)
Most instructions tell you to let the product sit in a cup of urine for a minimum of 40 seconds or more. But we’ve found most strips work even when just strategically placed in a stream of urine. If you’d rather pee in to a cup, disposable dixie cups are a great option.
- Wait up to a minute for the reagent and color to fully develop
Now is a good time to go and check that ‘gram.
- Compare your results to the keto strip color chart
Hold your now incubated ketone strip close to the color chart on the bottle to measure your current ketone levels. Match it to the closest color to get your best result.
- Dispose of your strips after using
Don’t be a monster! Your spouse/roommates/friends will thank you.
Pro Tip: Find the best time to use your strips
Certain parts of the day, like in the early morning or after dinner were shown in a NIH study to have the highest and most reliably detectable levels of ketones
Tired of peeing in to cups? Us too.
That’s why we made the Keyto – measure how deep you are in to ketosis with a single breath. No more gross pee cups, no more disposables. Order yours on Indiegogo now
Not sure about your keto strips’ accuracy?
Are your strips not working?
To keep your results as accurate as possible, be sure to do the following:
- Test different methods of testing – some users report different results when urinating directly on the strip vs. peeing in to a cup. I personally haven’t found a difference, but experiment to see what works best for you and your brand of strips
- Replace the cap after taking out strips
- Don’t expose the strips to strong light or moisture
- Don’t remove the desiccants (they’re there for a reason!)
- Don’t get the testing area dirty and try to avoid touching it with your fingers
- Check your expiration dates!
The best keto strips, according to Amazon
Perfect Keto ketone test strips
Perfect Keto’s stylish and minimalistic packaging almost looks more akin to beauty supplies than pee strips. But users like the clear color changes and think they’re easy to use as long as you follow a low carb diet.
SmackFat keto test strips
Smackfat’s keto test strips boast an impressive 5,000+ reviews on Amazon. Like the Perfect Keto test strips mentioned above, Smackfat’s strips come 100 to each bottle. Many users mention enjoying using them in the earlier stages of ketosis, but found the legend to be initially confusing. For best results, aim for the darker colors in the legend which indicate you’re actually in ketosis.
The Problem With Pee Strips
The problem with using pee strips for keto is that once you become fat-adapted, it can be difficult to measure ketosis using blood or urine. This is because as your body gets better at using ketones for fuel, so fewer ketones will be found in your bodily fluids. This is why we like using breath analysis over urinalysis for ketosis, and why we made the Keyto. Order yours here on indiegogo.
What level of ketosis is ideal for weight loss?
Try to aim for 1.5 – 3 mmol/L for optimal ketosis. Anything less than this amount is considered a trace amount.
How are keto strips’ accuracy?
Due to the variation of ketone presence depending on time of day, we think ketone strips are a good way to measure whether or not you’re in ketosis, but blood and breath tests have shown to be more granular and reliable in our testing and other online reports. Some online reviewers complain of receiving “bad batches” – even with highly rated items.
Not sure where to buy keto strips?
The easiest place to buy sticks online is through a retailer like Amazon. However many companies sell keto sticks in store to aid diabetics who are monitoring their ketone levels. Remember, availability will likely vary by store so call your store before heading over. The following brick and mortar stores sometimes sell keto urine sticks:
- Rite Aid
Ketone urine-testing strips, also called Ketostix or just ketone sticks … are small plastic strips that have a little absorptive pad on the end. This contains a special chemical that will change colour in the presence of ketones in the urine. The strips may change varying shades of pink to purple, or may not change colour at all. The container will have a scale on the label, with blocks of colour for you to compare the strip after a certain time lapse, usually 15 seconds. Most folks simply hold a strip in the flow of urine. However, the force of the flow can “wash” some of the chemical away, experts advise that a sample of urine be obtained in a cup or other container, then the strip dipped into it.
The chemical reagent is very sensitive to moisture, including what’s in the air. It’s important to keep the lid of the container tightly closed at all times, except for when you’re getting a strip to take a reading. Make sure your fingers are dry before you go digging in! They also have an expiry date, so make note of this when you purchase the strips … that’s for the UNopened package. Once opened, they have a shelf-life of about 6 months — you may wish to write the date you opened on the label for future reference.
Ketone test strips can be purchased at any pharmacy, and are usually kept with the diabetic supplies. In some stores they’re kept behind the counter, so if you don’t see them on the shelf, just ask the pharmacist; you don’t need a prescription to buy them.
The Best Keto Strips to Measure Ketosis
If you’re following the keto diet, one of the first things you likely learned was that filling your plate with lots of healthy fats (think salmon, avocado, nuts, and seeds) and cutting way back on carbs can eventually put you in ketosis. In this metabolic state, your body burns stored fat instead of carbohydrates, which can lead to weight loss.
But how do you actually know whether or not you’ve achieved ketosis—and make sure you stay there?
Enter keto strips. “They test levels of ketone bodies, which you produce when you’re following the keto diet correctly,” explains doctor of natural medicine Josh Axe, founder of DrAxe.com, author of the upcoming book Keto Diet, and a member of The Vitamin Shoppe Wellness Council. “Testing your ketone levels is a way of providing real-time feedback about how well your diet and lifestyle choices are working to keep you in ketosis.”
RELATED: 4 Things You Need to Know Before Trying the Keto Diet
Types of keto strips
The main ways to measure ketosis are with urine keto strips and blood keto strips. Urine keto strips are affordable and easy to use, but there are some drawbacks, Axe tells us.
” don’t measure all three types of ketones,” he says. “They measure acetoacetate, one of three ketone bodies, but not BHB (beta-hydroxybutyrate), which is considered the predominant ketone that’s produced.” Over time, he adds, it’s possible for urine keto strips to become slightly less accurate as your body becomes more keto-adapted.
If you’re someone who’s just starting keto or prefer to test for ketosis quickly and cheaply, urine keto strips are probably all you need. But if you’ve been following the diet for some time and want super accurate results, you might consider a ketone blood meter instead.
“Many consider blood keto tests to be the most reliable and accurate way to test for ketones, since this is actually the same method that people with diabetes use to test their blood glucose levels,” says Axe. Blood tests are less likely to be affected by hydration levels, food consumption, or recent exercise, he explains.
Hate the idea of pricking your finger? In the future, testing ketones might be even easier: A new keto breathalyzer called Keyto is currently crowdfunding on Indiegogo.
RELATED: Your Ultimate Keto Diet Grocery List
How to use keto strips
Urine keto strips are pretty straightforward, especially if you’ve ever taken a pregnancy test. Although instructions may vary slightly depending on the brand, most recommend that you pee into a cup (we suggest stocking up on some cheap paper cups), dip the strip into your urine for a few seconds, then wait for the strip to change color. An accompanying keto strip color chart helps you determine your ketone levels.
Blood keto strips usually instruct you to prick your finger to draw blood into the strip, then insert it into your meter. Getting set up with this method is a little more involved, however.
“You’ll need to initially invest in buying the device itself, compatible test strips, and a lancet device to prick your finger,” says Axe. He also recommends taking time to read reviews so you fully understand how different devices work. “For example, some work with an app on your phone; some require you to pay for a monthly subscription.”
Regardless of whether you’re using urine or blood strips, “most experts recommend testing fasted ketone levels right after you wake up in the morning,” says Axe. “You don’t want to be very dehydrated when testing, since this will alter your results and show higher levels of ketones.”
Ready to start testing those ketones? Below, some of the best keto strips (for both blood and urine testing) you can buy online.
RELATED: The 7 Best Keto Snacks You Can Buy on Amazon, According to Nutritionists
With so many 8fitters asking about – and trying – the ketogenic diet, we want to make sure have all of the resources at hand before you give this restrictive diet a go. The ketogenic (or keto) diet is a low-carb, high-fat (LCHF) diet that sends your body into a state of ketosis. In this state, your body begins to use dietary fat and body fat as fuel because it doesn’t have carbohydrates to burn. This metabolism of fat creates molecules called ketones – something you can measure for with ketone test strips.
That’s a lot of keto-this and keto-that. Let’s break it down:
Ketogenic diet: The low-carb, high-fat and moderate-protein diet that brings your body into a state of ketosis
Ketosis: The state when your body starts burning fat for energy instead of carbohydrates which is brought on by a ketogenic diet
Ketones: The molecules produced when the body metabolizes fat (i.e. breaks fat down for energy); the more fat metabolized, the greater number of ketones created
How to test ketones
There are a few ways to detect whether or not your body has entered a state of ketosis. First, you’ll likely experience what they call the “keto flu” – an one to three-day adjustment period when your body transitions to burning fat for fuel. Other changes you might observe in your body are:
Keto breath: The smell of your breath changes as you enter a state of ketosis. It might smell fruity or metallic, but the scent will diminish after a few weeks. If you don’t notice the change, ask someone close to you or consider purchasing a reusable keto breath meter. Typically priced at about $200, these meters measure acetone levels in the breath – which is what’s causing the change in smell.
Increase thirst: In the beginning, your body starts to use up excess glycogen stores, increasing the need for urination. As the body expels excess sodium and water, it’s recommended to balance electrolytes with 2-4 extra grams of sodium per day (thats about ½ to ¾ teaspoons).
Keto test strips
Another more reliable way to test ketones is using keto test strips. There are two main types of keto strips – ketone urine test strips and ketone blood test strips. We’ll go through how to use them both.
Ketone urine test strips
More accurate than tuning into your the smell of your breath or your thirst level, keto urine strips are a quick and relatively inexpensive way to measure ketones. You can buy these at almost any pharmacy, drug store or even the supermarket. Look for the brand name Ketostix. To use the strips, simply pass the test end through your urine stream or collect your urine in a clean, dry container and dip the end of the strip into it. Wait 15 seconds.
Now, let’s talk about how to read ketone test strips. The urine strips have a color chart that measures ketone bodies from trace amounts all the way to large amounts. Deep purple generally indicates higher levels of ketones. But, high amounts of ketones doesn’t mean you’re in a more desirable state. A low-to-mid level is often linked better overall well-being.
Some notable keto urine test strip brands include:
Kiss My Keto
Ketone blood test strips
More accurate than breath, thirst and urine tests are blood tests. While they the most accurate, they are also the most expensive method for measuring ketones and are typically executed under medical supervision and reserved for diabetics or prediabetics. To test ketone levels this way, you need a blood ketone meter and a kit that includes a lancet pen and ketone blood test strips. The body is typically in ketosis when the blood ketone meter measures between 0.5 and 3 mml/L.
Ketone test best practices
Now that you know how to detect whether your body has entered a state of ketosis, let’s fine-tune your method with these best practices. Remember, you can often feel if your body is producing a higher volume of ketones because you may experience the keto flu, a change in breath smell or increased thirst. To double check, purchase some at-home urine test strips and follow these tips:
Use strips regularly during the beginning phases of a ketogenic diet
Test your ketone levels a few times per day; fluctuations might occur after waking up, following a meal or exercising
Keep a food journal and include glasses of water as both meals and hydration impact ketone levels
Aim to maintain blood ketone levels between 0.5 and 3 mml/L (.05-1.5 mml/L being a state of nutritional ketosis, closer to 3 mml/L being a state of post-exercise ketosis)
Avoid paying for ketone blood test or blood test strip kits until you understand how your body responds to the ketogenic diet
Get help with your ketogenic diet with our comprehensive keto guide below. If you’re interested in a personalized meal plan — which you can customize to be low-carb, sign up for 8fit.
Last Updated on October 3, 2018
Many people following keto diets want to be in ketosis, a natural state in which the body burns fat for fuel.
For this reason, people are curious about whether they are doing enough (via carb restriction) to achieve this state.
As a result, ketone strips are a popular tool that numerous people use as a way of measuring ketosis.
However, just how accurate are they?
And how do they compare to alternate methods of measuring ketones?
What is Ketosis?
Anyone following a standard high-carbohydrate diet will be burning glucose for energy.
However, the body can use both carbohydrate and fat for fuel (1).
When carbohydrate intake is very low, the body switches to burning fat for energy. As this happens, our body enters a state of ketosis.
Ketosis is a natural biological state during which our body burns fat for fuel. While we are “in ketosis,” our blood levels of ketones—a by-product from the breakdown of fats—rise.
Measuring these ketones (also known as ‘ketone bodies’) can, therefore, provide a hint as to how deeply our body is (or isn’t) in ketosis.
For this reason, ketone strips—which measure the level of ketones—have become increasingly popular in recent times.
Key Point: Ketosis is a biological state where the human body burns fat rather than carbs.
What are Ketone Test Strips?
For people who want to know if they’re in ketosis, ketone test strips are a cheap and simple way of detecting ketone levels.
They are otherwise known as ‘ketone sticks’ and work by urinalysis to tell us the volume of acetoacetate in our urine.
If you don’t know what acetoacetate is, then let’s start at the beginning.
First of all, there are three types of ketone body;
Acetoacetate is one of the two main ketone bodies, and it is present in urine.
We can test for it by using ketone strips.
Beta-hydroxybutyrate is created from acetoacetate, and it is the second of the main ketone bodies.
This ketone body shows up in our blood, and blood ketone meters can tell us the volume.
Acetone is also a ketone body, although not as prevalent as acetoacetate and beta-hydroxybutyrate.
The breakdown of acetoacetate produces acetone, and it is present in our breath.
How Do Ketone Strips Work?
You can probably guess the finer details, but if you want to know how to use ketone strips, the process looks like this;
- Take a urine sample in a clean container/jar of some sort
- Hold the end of the strip in the urine for a few seconds
- Shake the strip to remove any excess “liquid” before removing from the container
- Wait 15 seconds until the ketone strip changes color
- Comparing the color of your ketone strip to the color chart will let you know if you’re in ketosis (and how deeply).
Here is a video of someone doing it;
Knowing how to read the ketone strip is important too, so here is the color chart;
The color on the far left means that no ketones are present, and the pink colors signify a light to medium state of nutritional ketosis.
As we move further to the right, the darker purple shades suggest a very strong level of ketosis.
Key Point: Ketone test strips are a urinalysis tool. They give people an indication of their state of ketosis by showing the level of ketones in urine.
What Level of Ketone Bodies is Best For Health?
For those aiming to be in ketosis, what kind of reading should we strive for?
I have a feeling that many will look at the table and automatically assume that ‘strong’ is best.
However, for the average person just looking to take care of their health—or maybe lose some weight—higher levels are not necessary at all.
If you’re in the ‘light’ range, then your body will be burning fat for fuel, and you’ll have ketone levels that are many multiples of the average person.
In short, aiming for a random ‘optimal’ ketone number isn’t the right approach.
Listening to your body and seeing how you feel? That’s the right way to go about it.
Note: If you are undertaking a ketogenic diet for a medical purpose, speak to your physician about this. Therapeutic ketosis levels may be very different to what the average person needs.
Key Point: Higher ketone levels are not necessarily better. For the average person, light/moderate ketosis is perfectly fine.
How Accurately Do Ketone Strips Measure Ketosis?
On the negative side, ketone strips are not always as accurate as most people believe.
For example, here are a few circumstances in which an inaccurate reading could be possible;
Ketones in Urine Don’t Give a True Indication of What’s Happening in the Body
In the first place, any ketones which go unused by the body are excreted via urine (2).
To put that differently, urine strips only show the number of excessive ketones that our body couldn’t use.
Therefore, just because the level of ketones in urine is small doesn’t mean that the levels in our blood are also small.
Nor does it mean that we are not in ketosis.
For this reason, blood ketone levels are a more accurate way of measuring ketosis than ketone test strips.
Hydration – Does Over/Under Hydration Affect Ketone Levels?
First of all, this idea relates to how well hydrated (or dehydrated) someone is, and whether this state impacts the ketone strip reading.
For instance, if someone is drinking large amounts of water, then it may dilute urine to the extent that affects the reading.
On the other hand, if someone is dehydrated, then higher concentrations of ketones may be present.
However, I’m not convinced that hydration greatly impacts the reading.
Ketone strips are designed for the average person consuming typical amounts of water. If someone is seriously dehydrated or drinking extreme amounts of water, then yes… this may potentially impact the reading.
But for the average person, I don’t think hydration should significantly affect these readings.
It takes time to adapt to burning fat for fuel.
For example, you may have heard about the ‘keto flu.’
This particular name refers to the often uncomfortable period during which the body learns to use fat for fuel rather than glucose.
In other words, when someone first starts a ketogenic diet, the body won’t be using ketones efficiently (3).
As a result, it’s likely there will be a higher concentration of waste ketones in the urine in the initial stages.
Over time and as the body adapts to burning fat for fuel, it should become more adept at burning ketones for energy. As this happens, the volume of ketones we excrete will fall.
Consequently, ketone readings may go down at this time.
This disparity may be confusing since your body will be more in ketosis, yet with a lower level of ketones showing on the ketone strip.
It is a reason why ketone sticks don’t tell the full story and why their accuracy isn’t always reliable.
Key Point: Ketone strips are not always 100% accurate, and the readings may fluctuate for a number of reasons.
What Are Some Other Ways To Measure Ketones?
There are three main ways of measuring ketones in the body;
- Blood meters (beta-hydroxybutyrate)
- Breath analyzers (acetone)
- Urine strips (acetoacetate)
As we have already gone through the latter, let’s look at the other two methods.
Ketone Blood Meter
Ketone blood meters are more accurate than testing by urine strips.
However, this extra accuracy comes at a higher price.
How do blood ketone meters work?
- First, you need to insert a blood ketone strip into the ketone meter.
- After this, prick your finger to draw some blood (don’t worry, it’s just a small drop like a standard blood glucose test).
- Put the blood on the ketone strip and check the results.
This technique is simple, and as previously mentioned, levels of ketones in the blood give a more reliable indicator of ketosis than urine levels.
Breath Ketone Analyzer
While ketone breath analyzers don’t offer the same accuracy as blood meters, they have some positive points;
- The initial purchase of the equipment is more expensive than ketone strips, but it’s a one-time deal. No more purchases are necessary. Unlike the other two methods, you can re-use the breathalyzer as much as you want. It’s by far the most cost-effective way of measuring ketones.
- It’s straightforward to use and doesn’t require urine or blood.
How do breath ketone analyzers work?
They are very simple.
All you have to do is turn on the breathalyzer and then breathe into it for however long the manufacturer instructs (about 15 seconds).
Wait for a few seconds and then check the results.
Key Point: Blood ketone meters and breath ketone analyzers are more accurate than ketone strips.
What is the Best Way To Measure Ketosis?
This question has no clear answer, and it depends on what you’re looking for.
- Ketone Urine Strips: Very cheap but low in accuracy compared to the alternatives
- Blood Meters: Highest degree of accuracy at the highest price
- Breath Ketone Analyzer: Expensive, but you only pay once since it needs no ketone strips. Probably somewhere in the middle when it comes to accuracy.
Ketone strips are a reasonably accurate—and cheap—way to detect someone’s (approximate) state of ketosis.
For someone attempting to ‘enter’ therapeutic levels of ketosis, ketone testing is a valuable tool.
However, they are probably not necessary for the average person who just wants to lose a bit of weight or finds a keto diet beneficial.
That said, they can be a useful way to check that those new to ketogenic diets are on the right track.
For information on when excessive ketone levels can be an issue, see this ketoacidosis guide.
The Performance Benefits of Ketosis
How can you tell if your low-carb dieting efforts have been effective enough to induce a state of ketosis? Learn how to check our ketones and detect ketosis.
This article is aimed at readers who’ve already done some research into ketogenic diets. A ketogenic diet is an extremely low-carb and high-fat diet, which has some potential side effects. Should you want to learn more about the ketogenic diet and understand the pros and cons, we recommend you read this article. Sign up for the 8fit app for a customized, low-carb meal plan.
A ketogenic diet consists of 70-75% fat, 20-25% protein, and 5-10% carbs. For an average person who requires 2,000 calories per day, that equates to a maximum of 50 grams of carbs per day. The average American woman eats more than 4 times as much (around 224 grams carbs per day).
Restricting carbs means less glucose
The body of a healthy person who gets their nutrition from a balanced ratio of macronutrients — protein, carbs and fat — burns glucose as their main source of energy. Glucose typically comes from carbohydrate-based foods (like bread, pasta, fruit, legumes, whole grains, soda, etc.). Those are used to provide the body with energy or stored in the form of glycogen in the muscles and liver. When calories or carbs are reduced strictly, there isn’t enough glucose available to the body. As such, it seeks an alternative strategy in order to meet the body’s energy demands and to keep functioning properly.
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The state of ketosis: Finding an alternative source of energy
The state of ketosis means that the body has switched from depending on carbohydrates for energy to burning fats for fuel. This means not only dietary fats (olive oil, guacamole, deep-fried pig ears) but also body fat — clearly a desirable state for anyone looking to shed extra weight.
When the body metabolizes fat, it generates molecules called ketones (also known as ketone bodies). As you restrict carbohydrate intake and amp up the dietary fat, more fat is metabolized and a greater quantity of ketones are created. Most of the cells in your body — including those in your brain — are able to use ketones for energy, although many people experience an adjustment period (1-3 days) often called the low-carb flu.
For healthy individuals, ketosis usually kicks in after 3 to 4 days of eating less than 50 grams carbs per day. It can also happen after a very long exercise session, during pregnancy or for people with uncontrolled diabetes.
Note: For a person on a 2,000 calorie ketogenic diet, carb intake should not exceed 50 grams, but the general recommendation is somewhere between 20 and 30 grams. In the infographic above, the macronutrient and meal recommendations are based off a carb total of 5-10% of a 1600kcal diet, amounting to 20-40 grams of carbohydrates per day.
How to detect ketosis
Following a very low-carb diet, with less than 50 grams carbs per day, does not necessarily mean your body switches to ketosis. For instance, exercising or eating too much protein can kick you out of it. There are different methods to find out if your body has switched to ketosis.
#1 Keto breath
Acetone is one of the three attributes of ketone bodies produced as a by-product when fatty acids are broken down for energy in the liver and kidneys. As a result of the released acetone, the smell of the breath changes when entering ketosis. It can be described as “fruity” or even “metallic” – it’s been likened to overripe apples.
If you notice this happening in your first few days of changing your diet, it could mean you’ve entered ketosis. Brushing, flossing or scraping the tongue doesn’t help to kill the bad breath, but it usually diminishes after the first few weeks.
Acetone can also be detected by using a Ketonix device, which measures the acetate/acetone concentration in the breath. Those devices are rather expensive and not always very accurate.
#2 Increased thirst and dry mouth
When shifting to a ketogenic state, thirst typically increases. The body uses up excess glycogen and increases the need for urination. Checking how thirsty you are is very inaccurate if you want to find out if you’re in ketosis.
As insulin levels decrease while following a ketogenic diet, the body starts expelling excess sodium and water. To balance electrolytes, it’s recommended to add 2-4 grams of sodium per day to your diet when following an extremely low-carb plan.
#3 Detecting ketones in urine
A more accurate way to check for ketosis is to use ketone urine testing strips, often referred to by the brand name Ketostix. The strips are inexpensive and help to check ketone levels quickly. If you’re in ketosis, the strip will change its color. The strips usually come with a guide to find out how “deep” the level of ketosis is.
Pass the test end of the small paper keto strip directly through your urine stream (alternatively, collect urine in a clean, dry container and dip the strip in afterward). Shake off any excess, then wait 15 seconds. The Ketostix color meaning is on a tonal spectrum that will show you what state of ketosis you’re in. Here is a short breakdown on how to read ketone strips:
If the keto strip changes color from its original beige — compare the color to the guide on the side of the bottle to find out how “deep” your level of ketosis is.
Deeper purple levels generally indicate higher levels of ketones. This doesn’t mean deep levels are a desirable state though. A low-to-mid level is often linked a better overall well-being.
Keep in mind that the ketone levels in the urine don’t necessarily match with ketone levels in the blood. For instance, the concentration of ketones in the urine changes depending on how hydrated you are. Dehydration may result in a false positive. This is likely to happen when testing ketone levels in the morning. On the other hand, drinking lots of water can result in a lower concentration of ketones, meaning a false negative.
Ketone strips color chart
This Ketostix color chart will help you assess whether you’ve reached ketosis, and if so to what extent. Make sure to wait precisely 15 seconds after the test strip comes into contact with the urine and compare the color of the test area to that of the corresponding spectrum below.
#4 Blood tests
Blood tests are the most accurate (and the most expensive) way to measure if your body has switched to ketosis. Blood ketone testing is typically used by people with diabetes. To test ketone levels, you need a blood ketone meter and a kit that includes a lancet pen and ketone test strips. Don’t confuse ketone test strips with glucose test strips as the latter won’t test for ketones.
The body is typically in ketosis when the blood ketone meter measures between 0.5 and 3 mml/L.
Potential errors from testing for ketones in urine
Ketone levels in the urine don’t necessarily match ketone levels in the blood. There are a couple reasons why this might be the case.
How hydrated you are can make a big difference regarding the concentration of ketones in your urine. Dehydration may result in a false positive, which some folks find happens every morning to a mild degree. Likewise, drinking a ton of fluids — and you should be drinking water like it’s your job — will result in a lower concentration of ketones, meaning a false negative.
As time goes on, people following ketogenic diets tend to measure lower levels of ketones in their urine despite still being solidly in fat burning mode. At this point, a blood test may be necessary to accurately test for ketosis — but these are significantly more expensive (plus, you have to prick your finger instead of simply urinate). If you’ve been following good eating habits and have been consistently in ketosis for the weeks following, there’s likely no need to fret over it.
Keto diets don’t always result in weight loss
Keep in mind that you do require fewer carbs if you maintain a non-stressful and sedentary lifestyle. However, it’s different if you work out regularly or have a demanding job. Carbs help the brain, the heart and the nervous system to function properly. It’s not necessary to cut carbs short in order burn fat.
Before switching to a keto diet, make sure to do further research. It’s not necessary to drastically reduce carbs in order to lose fat.
Being in ketosis generates elevated levels of ketones, which are detectable in the breath, urine, and blood.
Ketone urine testing strips (like Ketostix) are the quickest, easiest way to test for ketones in urine.
Hydration and amount of time spent in ketosis may affect Ketostix (urine test strip) results.
Ways of how to check your ketones include ketone urine testing strips, blood tests, increased thirst or a change of your breath smell also known as keto breath.
The best way to test ketones in blood, breath or urine
Ketones in your blood… ketones in your breath… ketones in your urine… When you are in ketosis, ketones are everywhere. Should you measure them? Why not? It is objective feedback, and it can be motivating. Perhaps knowing where you actually are, physiologically, will give you that nudge to reach your goal. Or maybe it will confirm you are already there. Either way, knowledge is power.1
This review, , is completely independent and free from industry influence.2
Ketone testing can be cheap and easy. But it can also be expensive and invasive. There are three basic categories of testing, each with its pros and cons. Accuracy, price and qualitative factors vary considerably across the options. If you are wondering what method might be right for you, this guide will provide answers.
In a prior guide, I compared four ketone meters that test blood ketone levels. I will use the winning meter from that review, the Keto-Mojo, and compare it to several options within each of two other categories of testing — breath and urine.
As with the ketone blood meter review, I’ll look at each contestant across three attributes: accuracy, price and qualitative factors. In the end, there will not be a clear winner, but you will really understand your options and the tradeoffs among them. Only you can decide which method is best for you.
1. The three types of testing: blood, breath and urine
Each method of testing measures something different: blood tests measure β-hydroxybutyrate levels, breath tests measure acetone levels and urine tests measure acetoacetate levels. β-hydroxybutyrate, acetoacetate and acetone are all ketones produced during fat metabolism. If you are burning fat, you are making ketones, so all three can be a gauge of ketosis.
When I am running on ketones, all three are present in my blood. Some acetoacetate molecules get excreted in urine, so I can measure their concentration as a proxy for ketone levels in the blood. Acetone is actually small enough to pass from the blood into the lungs, so small quantities are present in exhaled breath.3
Because each method is different and there is no linear relationship between the different ketone measurements, direct comparisons between two methods is not possible. However, I ran each method through the same protocol at essentially the same point in time, so I will have compatible data and user experience to consider across each method.
If you purchase a blood ketone meter, you get a reading of the amount of β-hydroxybutyrate circulating in your blood. It requires a finger-stick to produce a very small drop of blood for testing, but is otherwise relatively quick and easy.
Blood ketone meters require a battery (included with purchase), but they do not have to be charged or plugged in. They require a test strip for each test (about $1/strip) and disposable lancets.
I have already tested blood ketone meters. In that review, they reliably tracked with commercial laboratory tests for β-hydroxybutyrate. Thus, I used the winning meter, Keto-Mojo, to benchmark other ketone measurements against blood ketone levels in this experiment.
Which is the best ketone meter on the market?
GuideAre you in ketosis? Are you sure? With a blood ketone meter, you can test for blood levels of beta hydroxybutyrate, a ketone that your body produces when in ketosis.
There are several different devices on the market that test for the breath ketone, acetone. They vary widely in design and price. I tested three: Ketonix, Keto Stat and LEVL.
The Ketonix requires some setup before use. It must be charged for about 12 hours and requires that you download an app onto your smart phone and pair it with the device before you can begin taking measurements.
Note that the Ketonix includes a rechargeable battery so that the device can be used when you are away from an electric outlet… convenient for camping, etc. I experimented with it, and although it is a little tricky to get the battery aligned with the device so that you can carefully connect the two, once completed, it worked well.
Once set up, a deep exhale — from the bottom of your lungs into the device — is all that it takes to get a measurement. This is not the same as a deep breath! The instructions emphasize using your muscles to force all the air out of your lungs.
During testing, I occasionally needed to close the app and reopen it to get it to reset and work correctly. On one occasion, I needed to unplug the device and plug it back in to reset it.
Can you test any time with a Ketonix? Not really. The manufacturer suggests waiting until alcohol is completely out of your system before testing. In my experience, even just a glass of wine could really skew the test toward much higher readings, suggesting the sensor struggles to distinguish alcohol from acetone.
The Keto Stat was simple to set up; it just required inserting a triple A battery.
After turning on the device, a countdown begins. When it reaches 0, a deep, 10 second exhale is required.
The LEVL requires considerable setup before use. It must be charged for 24 hours and requires that you download an app onto your smart phone and pair it with the device before you can begin taking measurements.
The LEVL also requires calibration, which takes about 10 minutes. Although relatively easy, it requires pressing the mode button in a particular pattern and then flushing test gas from two cylinders into the breath pod and calibrating the device with each gas. If you are intimidated by mechanical things or following directions, this might not be the device for you. Note that calibration must be repeated every two weeks (and every time you unplug the device for more than a couple of hours).
Once calibrated, all that is required is to raise the lid and press the mode button to select the user. Then, after holding your breath for at least 5 seconds, exhale into the test pod, place the pod in the device and close the lid.
LEVL also suggests that you replace its sensor module every month ($50 part). This requires an Allen wrench (included) and a Phillip’s head screwdriver, plus pressing the mode button in a particular pattern. Again, the instructions are clear, but this level of mechanical tinkering is not for everyone.
The LEVL does not have a battery option, so it can only be operated when connected to a wall outlet.
LEVL cautions against testing within 60 minutes of the following: Alcohol, breath mints, chewing gum, cough drops, throat lozenges, tobacco and e-cigarettes, lip balm, smoking, mint or green tea, mouthwash, non-sugar sweeteners (e.g., Sorbitol), toothpaste, water enhancers. (In my experience, alcohol skews the LEVL readings for much longer than an hour.)
The low-tech way to test for ketosis is with urine test strips designed to check for the ketone acetoacetate. There are many commercial brands available on Amazon. I tested four brands: Kiss My Keto, Nurse Hatty, Smack Fat and Top Notch.
All of the strips look pretty much alike, although the Nurse Hatty strips are longer — 4.25” vs. 3.5” — perhaps making them a bit better for mid-stream testing. All brands use the identical chemical, sodium nitroprusside (at 7.1% for most, but 7.7% for the Nurse Hatty brand), to check for acetoacetate.
The instructions for use varied. Two of the brands, Top Notch and Kiss My Keto, suggested reading the ketone strip 15 seconds after dipping it in urine for 1-2 seconds. The Nurse Hatty brand directed a 40 second waiting period before reading the strip. The Smack Fat brand recommended submerging the test strip in a urine sample for 40 seconds. (Note that the Smack Fat strips worked using the “dip and wait for 15-40 seconds” method, too.) In each case, I followed package instructions.
My testing procedure was pretty straightforward. After a fast of 12-14 hours, I took two ketone reading from the same blood sample on the Keto-Mojo.4 These blood ketone levels served as a benchmark for the breath and urine tests. (I believe these readings are fairly accurate, as the meter performed well when repeatedly compared against a laboratory test for β-hydroxybutyrate. See our blood ketone meter guide for more.)
Immediately after the blood test, I used the breath testing equipment, four times for each device. I then moved straight to the urine strips, with four back-to-back readings from each of the brands. Finally, I tested my blood again with two more readings from the Keto-Mojo.
I repeated this procedure five times, on five separate dates.
The repetitive design of the experiment allowed me to evaluate the ketone measurement devices several times (4 readings across 4 tests, so 16 readings in total for each brand), which allowed me to look for both precision and internal consistency.
I chose to test when I was in full-blown ketosis, in moderate ketosis (twice) and out of ketosis, so I could see if the brands perform accurately in different conditions. This would also help me judge whether the measurements tell me what I ultimately want to know: Am I in ketosis, and if so, to what degree?
|Test #1||Test #2||Test #3||Test #4||Test #5|
|Test #1||Test #2||Test #3||Test #4||Test #5|
|Test #1||Test #2||Test #3||Test #4||Test #5|
|Kiss My Keto||moderate||moderate||trace||none||none|
As you can see in the above results, with the exception of the Keto Stat breath meter, which was completely ineffective, all of the brands tested gave a decent indication of my level of ketosis. However, the Keto-Mojo disappointed, with higher-than-expected readings on the “Out of ketosis” tests.
For the fourth test, I had been eating carbs for a few days and expected to be out of ketosis. The Keto-Mojo gave me elevated readings, but the other methods showed I was out of ketosis. I figured it was some sort of fluke, so I ate more bread and tried again the next day (bonus 5th test). Again, the Keto-Mojo was mixed, but high enough to indicate moderate ketosis, whereas the other methods showed no ketosis.
At this point, I pulled out another blood meter (on hand from the earlier blood ketone meter guide testing) and got a “Lo” reading, matching the breath and urine testing. It would seem that my Keto-Mojo “benchmark” had it wrong… Why? It is hard to say. Given how well the meter performed in the last experiment, I can only guess that perhaps the set of 50 test strips that I purchased to begin this new experiment were slightly off. Perhaps the lesson is that however you test, if something doesn’t make sense, you might have a device issue.
The Ketonix and LEVL are reportedly measuring the same thing (concentration of acetone in the breath, in parts per million). However, the results between the two devices diverge considerably. Which is correct? I don’t know, and I am not sure that this really matters. If you purchase one of these devices, you will come to know what the numbers mean for you based on repeated testing in various conditions.
Ketonix suggests that therapeutic ketosis begins at about 4.0 parts per million. This matches up well with the testing I did. The first and second test showed levels well above 4.0 ppm, and the next test was borderline. The last two tests were both below 4.0 ppm.
LEVL suggests that fat burning begins at 2.0 parts per million, essentially suggesting I never left the fat burning state. The only reading I ever got below 3.6 was 0.0, when I put a breath pod into the machine without exhaling into it. However, given individual variation, my feeling is that the LEVL readings, relative to one another, were quite consistent. The deeper my state of ketosis, the higher the LEVL reading.
Out of ketosis (4 brands) In ketosis (4 brands)
The four brands of urine strips were indistinguishable, performing identically to one another. Based on this, I see these as a commodity product — my guess is that any reputable brand works and it is fine to shop based on price.
The color codes for interpreting strip color for the Kiss My Keto brand show a creamy, less fleshy color for the negative… I believe the other brands color charts are more accurate based on the colors I observed on the strips.
Under the umbrella of accuracy, I would like to address two qualities and how they differ across the testing methods — precision and consistency.
The testing methods vary in terms of precision, by which I mean the exactness of the ketone measurement.
The digital meters (both blood and breath) give you a numerical reading, whereas the urine strips give you a color range. If you are into precision, you may struggle with the lack of an exact measurement provided by the urine strips; although directionally accurate, sometimes, a color can be between the colors on the chart. Ultimately, the urine strips give you a sense of where you are, but not an exact reading.
Test #1 Test #2 Test #3 Test #4 Test #5
There are larger questions about the precision of the urine strips. Individual levels of acetoacetate in urine vary, and even within a particular individual, there is evidence that as the body becomes more accustomed to burning ketones, less acetoacetate spills into the urine.
As reported in The Art and Science of Low Carb Living (page 164), as keto-adaption progresses, an individual may find that he or she is producing lower levels of acetoacetate in urine, even while blood levels of β-hydroxybutyrate remain constant. So urine strips may or may not work well for you. That said, although I spend much of my time in ketosis, enough acetoacetate was present in my urine to give a good indication of my level of ketosis.
Another aspect of accuracy is internal consistency. By this I mean, when testing the blood, breath or urine at roughly the same point in time, do I get the same result? For this reason, I tested each method four times at each testing occasion.
On this metric, all of the testing regimes performed reasonably. The Keto-Mojo bounced around a bit, particularly on the 5th test where it was struggling in general.
The exact reading of the Ketonix varied a bit among the four data points for each test, but within a fairly tight band. With each and every test, it was internally consistent regarding whether I was in deep ketosis, in moderate ketosis, or out of ketosis.
Likewise, the LEVL device showed variation at each test point, but remained internally consistent with average levels steadily decreasing as my level of ketosis diminished.
Finally, the urine strips were very consistent at each test point. When I dipped four strips in the urine sample at the same time, the color was always identical across the four strips (and across the four brands as well).
Test #1 – 4 strips from two different brands
The Keto Stat was so consistent that it gave me a 0.00 reading for every test, regardless of my level of ketosis, making it essentially useless. That is too much consistency! As a result, it is disqualified.
With any testing system, a potential customer should consider the total system price — the price of the initial investment for equipment (if any), plus any ongoing expenses for necessary extras (like, in the case of the blood ketone meters, more test strips). The number of tests desired varies widely by user.
For this review, I will look at a user who tests 200 times, or a little more than once per day, over the course of six months.
The blood ketone meter pricing is as follows:
|Brand||Starter kit||200 test strips*||200 lancets||Cost for 200 tests|
* 10 strips included in the starter kit.
The breath ketone meter pricing is as follows:
|Brand||Equipment||Extras||Cost for 200 test|
|LEVL||$699||$250 for five extra sensors||$949|
Urine strips are the least expensive way to test:
4. Qualitative factors
Accuracy and price are definitely important. But what else should you consider?
Are you comfortable with fairly detailed set-up instructions? If not, setting up the LEVL might be a bit much.
- Keto-Mojo: Insert code strip from test strip container. Good to go!
- Ketonix: Charge for 12 hours. Install app and pair with device.
- LEVL: Charge for 24 hours. Install app and pair with device. Calibrate, which involves pressing buttons and flushing two separate test gases into the breath pods.
- Urine strips: Open container. It couldn’t be any simpler.
Because some people prefer not to mess with bodily fluids… If that’s you, you might prefer a breath meter.
- Keto-Mojo: Needles. Blood. Need I say more?
- Ketonix: Just breathe!
- LEVL: Just breathe!
- Urine strips: Umm… urine.
Reliance on electrical power varies. How high or low-tech do you want to go?
- Keto-Mojo: Runs for a long time on the (included) battery.
- Ketonix: Must be either plugged into the wall or plugged into a rechargeable battery (included).
- The LEVL requires pretty much constant power; if you unplug for long, you will have to recalibrate the sensor.
- Urine strips: Powered by the chemical reaction! (Needs no power at all.)
Ease of use
Because more steps means more room for error… Which of these methods is the simplest?
- Keto-Mojo: Prick your finger, squeeze out some blood, insert a disposable strip into a meter and test.
- Ketonix: Open app and exhale.
- LEVL: Open app, press mode button, hold breath, exhale into breath pod, place in unit and close the lid.
- Urine strips: Remove a strip, pee on it and compare color to bottle.
Will your glass of wine with dinner taint your results? If you buy a breath meter, the answer is yes.
- Keto-Mojo: blood alcohol levels do not affect ketone blood tests.
- Ketonix: The sensor will confuse alcohol in your breath with ketones, giving you elevated results until the alcohol is out of your system.
- LEVL: The sensor will confuse alcohol in your breath with ketones, giving you elevated results until the alcohol is out of your system. The manufacturer also recommends waiting an hour to test after consuming things like green tea and mint, smoking or brushing your teeth.
- Urine strips: Alcohol does not affect urine tests for ketones.
Do you want to store and track your ketone results? Some products make that really easy; others don’t.
- Keto-Mojo: The meter saves data, but you can also purchase a Bluetooth adapter ($25) to export data and/or connect up with Head’s Up Health. ($9/month).
- Ketonix: An export of data to a CVS file is free, as are basic graphs of trend lines within the app. You can also integrate your Ketonix data with Head’s Up Health ($9/month).
- LEVL: The app saves data, and you can integrate your LEVL data with Head’s Up Health ($9/month).
- Urine strips: No data, here, unless you collect it manually.
Do you like a lot of feedback? Might you want to test several times a day just to see where you are? If so, consider the cost of incremental tests.
- Keto-Mojo: About a dollar per test.
- Ketonix: No incremental cost.
- LEVL: No incremental cost per test, but ongoing sensor replacement each month.
- Urine strips: About a nickel per test.
Here is a quick summary of where each method excels (and doesn’t). Overall, we love the Ketonix for its easy, ick-free operation and the urine strips for their lack of set-up and ease of use!
Green light means thumbs up… red light means thumbs down… yellow is somewhere in-between.
5. Pros and cons
Keto-mojo — the gold standard? Not always
(Price listed is for equipment and enough supplies to conduct 200 tests.)
- Accurate at high ketone levels.
- Data support options and alcohol-friendly.
- Inaccurately high readings when out of ketosis. (Bad strips?)
- Expensive ($250).
- Testing requires a tiny blood sample and several steps.
- Strips cost about a dollar, so costs add up if testing frequently.
Ketonix — high-tech made easy
- Easy to use, with data support options and no incremental cost per test.
- No bodily fluids.
- Expensive ($250).
- Requires set-up and either power supply or rechargeable battery.
- Alcohol interferes with readings.
LEVL — very pricey and high-maintenance
- Easy to use, with data support options and no incremental cost per test.
- No bodily fluids.
- Extremely expensive (~$950) and lots of maintenance.
- Requires set-up and a power supply.
- Alcohol, and many other things like mint and green tea, can interfere with readings.
Urine strips — Old-school but may get the job done
- Very inexpensive (~$11).
- Easy to use, alcohol-friendly and incremental tests do not cost much.
- Internally consistent, but not very precise.
- May not work for everyone.
- No data options and involves bodily fluids.
How should you test for ketones? That’s really up to you. All three methods can provide useful feedback.
Personally, I found the breath meter Ketonix to be reliable, easy, and fun to use. It hits the same price point as the blood ketone meters, and I liked not having to take a blood sample. When I send these devices back to the Diet Doctor office, it will be the one I miss the most!
But for you as a potential buyer, it is really a trade-off between accuracy, price and the qualitative factors that YOU care about most. Which one suits your wallet, needs and personality?
Ketosis is the process of burning body fat for energy and can be measured when following a low-carb ketogenic diet.
You don’t have to test for ketones for a ketogenic diet to work but some people may find it helps to check they’re on track and to tailor their diet towards more effective weight loss.
Whilst ketosis is a natural process in the body, it’s important to know the safety implications of being on a ketogenic diet which will apply to people on certain diabetes and blood pressure medications.
How measuring ketosis can help
Whilst we can all measure our weight to see whether weight loss is occurring, there are a number of reasons why measuring ketosis can be better.
Our weight can go up and down through the day but this won’t tell us whether we are actually burning body fat. Simply going to the toilet, for example, will involve a certain loss of body weight but that won’t give us any idea whether we’ve burned any body fat over the past hour or two.
Additionally, if you’re exercising and putting on muscle , the scales will only show weight loss stalling or a gain in weight and won’t show you whether you’re gaining muscle whilst also losing body fat.
Measuring ketone levels can help much more directly therefore as the production of ketones is a direct result of fat burning.
Just as blood sugar levels vary through the day, depending on what we’ve eaten and how our body is coping with metabolising the food, ketones levels can also change through the day in response to the food we eat and how our body copes in response.
How to measure ketones
There are a few different methods of measuring ketones which each have their pros and cons.
Urine ketone strips
Urine testing strips are cheap but measuring ketones in the urine rather than the breath or blood tends to be less accurate as ketones. The results from urine testing strips also reflect ketone levels over the past few hours rather than at the time of testing.
Testing ketones in the urine is good if you just want a rough idea of the level of ketosis you’re hitting.
Blood ketone tests
Blood ketone tests can be performed using certain blood glucose meters that have been specifically designed to test for ketones.
Blood tests are the most accurate method of measuring ketone levels but the cost of the test strips is relatively expensive if you intend to test your ketones on a regular basis.
It is possible to measure ketones on the breath. The method is not as accurate as blood ketone tests but is better than urine test strips.
Another advantage of using a breathalyser is that it involves a single up-front cost, which means that once you have the device, you can test your ketone levels as often as you wish.
This can be useful for people looking to seriously understand how well they’re achieving ketosis through the day.
At the time of writing (November 2016), a ketone breathalyser costs roughly £150.
When to measure ketones
When and how often to test ketones will depend on what you’re looking to find out.
If you’re looking to compare whether you’re keeping in ketosis from day to day or week to week, then it makes sense to test at the same time (or times) of day. This will ensure you get consistent results.
As ketones vary through the day, and are affected by different types of meal and exercise , you may want to test at different times through the day to see how your level of ketosis varies.
The ketone breathalyser is very useful for this as you don’t pay for each test as you do with say blood ketone testing strips.
The sweet spot for weight loss is 1.5 to 3.0 mmol/l. This level of nutritional ketosis is recommended by researchers Stephen Phinney and Jeff Volek.
Ketone levels of 0.5 to 1.5 mmol/l, light nutritional ketosis, is also beneficial although not to the degree of full nutritional ketosis.
The longer you stay within these levels, particularly within the sweet spot of nutritional ketosis, the more fat you will burn and the more effective your weight loss efforts will be.
If you are starting (or re-starting) a ketogenic diet, it can take up to a few weeks for your body to switch to using ketones as its main fuel source so don’t give up too early.
A number of factors can influence the achievement of ketosis. Carbohydrate intake, protein intake and level of exercise are primary factors.
For detail on how each of these factors can affect ketosis and weight loss, read our guide to weight loss on a low-carb diet
Ketosis with type 1 diabetes
Ketosis becomes a slightly more complicated topic when it involves people with type 1 diabetes or that are otherwise completely reliant on insulin.
If this applies to you, it is important that you understand the difference between ketosis and ketoacidosis If you are in any doubt, it’s important that you discuss your insulin management with your doctor or consultant.