Do Ketones Matter?

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A low-carb diet is, indisputably, one of the most effective ways to lose excess body fat. Over and over again, studies have proven the myriad benefits of carbohydrate restriction. Being fat-adapted brings several advantages, as you will have access to your greatest energy store - body fat.

Do More Ketones Enhance Fat Loss?

Contrary to what you may have thought, high levels of ketones will not guarantee enhanced fat loss. When you are in ketosis, the level of ketones in your bloodstream won't tell you how much fat you are burning. It will only tell you how much energy you currently have in your "fuel tank". Your body continuously produces and consumes ketones and over time, it will adapt and optimise the level of ketones in your body.

Do Ketones Matter?

Let's look at the evidence. This review of studies found a correlation between fat loss and the level of acetone, one of the ketone bodies that can be measured with a breath ketone meter. However, studies that are listed in the review compare the effects of a standard low-fat, high-carb diet to a high-fat, low-carb diet. As we know from several studies, low-carb diets over-perform high-carb diets. However, if we want to see how ketone levels affect fat loss, it would be necessary to compare low-carb diets and effects of different levels of carbohydrate restriction.

High ketone levels over 3 mM (also known as starvation ketosis) may, in fact, slow down fat loss. High ketone levels will likely elevate your insulin levels and as a result block the release of free fatty acids from your cells.

Ketosis is Not Just a Tool for Weight Loss

It's simple: if you want to lose body fat, you need to stay in calorie deficit and use your body fat for energy. A low-carb diet is a great tool that will help you achieve that. With stabilised glucose levels and low insulin levels, you will naturally eat less and your body will release and burn body fat for fuel.

Although losing weight is the most common reason people follow a low-carb or ketogenic diet, it's not the only reason and it's actually not desirable in some cases. Those who use the ketogenic diet for therapeutic purposes such as managing epilepsy or cancer may want to maintain or even gain weight. So do athletes who use a keto diet for top-level performance.

Should I Measure Ketones?

A blood ketone meter, which is the most accurate way to measure ketones, will measure the level of BOHB in the body. A breath ketone meter is another fairly accurate option for those who need to measure their ketone levels.

Do Ketones Matter?

Ketone levels vary for individuals, especially when we take keto-adaptation into account. Remember, you can learn how much you have in your "fuel tank" but not how much your body is using for energy.

Compared to someone who just started following a ketogenic diet, keto-adapted individuals will likely show a lower level of ketones simply because their body can use them more effectively than in non-keto-adapted individuals.

So, should you measure ketones? As you might have expected, it depends. I rarely measure my ketone levels. I've been following a low-carb diet since 2011 and I know what to eat and avoid to stay on track. Below I list the most common cases when measuring and tracking your ketone levels can be useful.

New to a Low-Carb Diet

If you just started following a ketogenic diet, measuring your ketone levels can be useful. Just like tracking and planning your diet, monitoring ketosis will help you avoid common mistakes while trying to stay low-carb.

To find out whether you are in ketosis or to learn how certain foods affect you, you can use a breathalyzer, a blood ketone meter or a blood glucose meter (same meter, just different strips). Don't focus on numbers and don't get discouraged when you see low ketosis readings - there are several factors that affect ketone levels.

Ketogenic Diet to for Therapeutic Reasons

If you use the ketogenic diet for therapeutic purposes (epilepsy, cancer, Alzheimer's, etc.), it's a good idea to track your ketone levels.

Ketogenic Diet for Top-Level Performance

Lastly, measuring ketones can be useful if you want to optimise your exercise - unless you perform at a top level, you don't need to do that.

Exogenous Ketones and Ketosis Supplements

I've been frequently asked about the use and effectiveness of exogenous ketones. Although they are likely beneficial for therapeutic purposes or top-level performance, they are unnecessary for the vast majority of people. I'm not a proponent of exogenous ketone supplements - I've tried them and wouldn't recommend them.

Unfortunately, products with exogenous ketones are marketed as weight loss products and their actual use is distorted. Endogenous ketones - ketones produced by the body as opposed to those that are supplemented - are a by-product of fat metabolism. Supplementing your diet with exogenous ketones will not make you burn more body fat. It simply doesn't work that way.

No matter what others will tell you, there is no miraculous pill or supplement that can do the job for you. If you want to lose weight, just stick with the diet. If you want to boost your energy, you can as well use coffee or MCT oil. If you want to learn more about exogenous ketones, here is a great post from KetoGains that goes into more depth.

Take-Home Message

  • The main reason why people lose weight on a ketogenic diet is well established: With stabilised glucose levels and low insulin levels, you will naturally eat less and your body will release and burn body fat for fuel.

  • Apart from anecdotal claims, there is no scientific evidence that high levels of ketones will guarantee enhanced fat loss. If you want to lose body fat, you need to stay in calorie deficit so you can use your body fat for fuel.

  • Typically, high ketone levels are desirable for therapeutic purposes or top-level performance rather than weight loss.

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By Martina Slajerova
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Martina Slajerova

I changed the way I ate in 2011, when I was diagnosed with Hashimoto’s, an autoimmune disease that affects the thyroid. I had no energy, and I found it more and more difficult to maintain a healthy weight.

That’s when I decided to quit sugar, grains, and processed foods, and to start following a whole-foods-based ketogenic approach to food.

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Comments (22)

What is your best go-to food for a quick pick me up. I teach school and between 2-3 I have a slump and start grabbing anything available. I know where all the teachers keep their chic stashes! They know me and laugh when I am desperate! What do you do? I also have Hashimotos but when diagnosed so many years ago they put me in thyroid pills. Thanks for your input and all this good info you put out.


So, earlier today, right after I worked out and ate lunch, my blood test for ketones showed to be 2.9. This evening after dinner it showed 3.4. How do I lower it, to remind in nutritional Ketostix?


I need help....this is my 11th day on ketogenic diet and never did I get a positive ketone result in my urine nor have I lost anything.
I even tried 2 days with only bacon, and nothing.  I have been adding coconut oil to all my coffees and food I cook and still nothing. I feel good and more energy.  I also walk about 2km a day.
I don't know what to do to kick my fat metabolism!!
please help
thank you


I just got a KETOnes meter and I'm at 0.8.  I've been doing Keto since Jun 2017 and today is Sep 2, 2017.  I've dropped 30 lbs (300-270) and I have to say I was worried about the .8 reading.  I didn't think I was in ketosis.  However, I think, based on all the reading, I'm in nutritional ketosis.   I'm going to keep this blog bookmarked.  Thank you.


There is empirical evidence that exogenous ketones induce nutritional ketosis without carb restriction:


Yes, that is true. However, you cannot out-supplement a bad diet. Supplementing with exogenous ketones without carbohydrate restriction is pointless.


You may have answered this already, but I seem to stay around that 0.4 mark and find it hard to get above that mark in ketones when measuring with the Precision Xtra. My glucose levels are always between 75-90, and maybe up near 99 after a meal, but never higher than that. Diet is around 80% fat, 15% protein and 5% carbs, all from green leafy veggies. I even try exogenous ketones and Bulletproof Brain Octane (C8 oil) and I struggle to get above 0.4. Any help?


Hi Eddy, low ketone levels are not necessarily bad. If you are keto-adapted, your body will use them for energy. Compared to that, people who just started following the keto diet may see high ketone readings because they are still glucose dependent and most ketones produced are not utilised for energy. Also, ketone levels fluctuate during the day - they are typically lowest in the morning and highest in the evening.


Hi Martina, I have been ketogenic for just over one year. I am at a point where I am hardly every hungry until around 5 pm when I usually eat dinner, so I am basically eating one meal a day. In the morning, I do have 2 cups of coffee with organic heavy whipping cream straight from the local creamery. Yesterday afternoon I tested my blood and my ketones were at a whopping 6.2 and my glucose was at 3.6 (I am in Canada so we measure differently to you). I am not diabetic or anything. I am thinking that perhaps I should cut out the full fat cream in the morning. I feel great besides that! What do you think?


Hi Jayne, what you describe is starvation ketosis. I don't think I've these readings even when I was fasting. If you are healthy (no diabetes), it shouldn't matter but such high readings are definitely not necessary. It's common not to feel hungry, but if it was me, I'd add some carbs from veggies.


Tried keto//os and no, thank you, never again. I've been keto for over 6 months and reached a plateau so I though this could help. I was already keto adapted and this made no difference. The taste was terrible... I mean really terrible... and made me sick for hours. It had no effect apart from making my ketostix dark purple = expensive pee. Just look at all the Amazon reviews and ignore the fake ones from their distributors.


I'm wondering if it's completely misused. I haven't tried it but my aunt did and said it did nothing to help her lose weight. I'm not sure if it was the same product though, I just know it had exo ketones. IMHO weight loss is a massive market and I guess that it's not profitable to sell it as a therapeutic supplement. They always say that it "may" help you lose weight... I hate that. MLM schemes are wrong and encourage their sellers to lie without anyone taking responsibility, just to get a nice cut. The sad thing is that anyone can sell it even if they haven't got a clue about the ketogenic diet.


Hi Martina, I'm new to your blog and enjoy every bit of information about keto dieting . I've been on a lchf diet now for 7 weeks and I'm still getting headaches. Is that something that will eventually disappear? I've also lost weight and body fat which I'm so happy about but I fluctuate 2 lbs up or down . Do you have any suggestions for me ? Thank you for what you do !


Hi Thelma, are you getting enough electrolytes? This could be "keto-flu". Although it's more common during the first few weeks of a keto diet (increased demean for electrolytes), you may experience it at any point, if your electrolyte intake (sodium, magnesium, potassium) is too low. Also, make sure you drink enough water - dehydration can be responsible for your headaches. Also, check out this post: How To Low Carb: 15+ Common Weight Loss Mistakes I hope this helps! 😊


If I have super high ketone readings and low glucose levels. Does that I have a excess amount of body fat?


Hi Re, no, it just means that you are in ketosis. When you say "very high", it also depends on what you use to measure your levels (blood ketone meter is very accurate but Ketostix may show high readings even when your blood ketones are low).


So did you notice any difference with the supplements or nothing at all?


Hi, yes, I did feel an increase in my energy levels but it wasn't different from what I experience with a cup of strong coffee. I didn't really feel like my mind was any "clearer"... Plus I had terrible digestive issues so I only took it for a few days because I couldn't literally leave the house. That's how it was for me and it might be different for individuals.


I think it's just this new hype where everyone is trying to get a piece... spammers from everywhere who know nothing about the diet. Just look at the videos on their websites.. it's like a joke. It works with everything new and popular and there you go, new MLMs for everything you can imagine... especially weight loss. Once people realize this, they won't care about super high keto levels.


The marketing model of these products is another whole topic... As a blogger with audience, I receive tens of spammy messages all over my social media and e-mail, especially from people who don't understand anything about nutrition and the products themselves.


Great quick blog post. I have had the same experience. I train high level athletes in ketogenic diets and are very successful just using food and adding coconut oil or a good olive oil. This ranges from weight loss goals to competitive CrossFitters, powerlifters and Wrestlers.
Thank, Jamie


Thank you Jamie!