Articles, Blog

What’s the Best Time to Test Blood Ketones? (And How Often)

January 25, 2020

Okay the bottom line is these blood
ketone strips are expensive and we don’t want to be wasting them. There are
several times during the day when testing will give you misleading
readings. By the end of this video, you’re going to know when you should be testing
when you shouldn’t be testing and how often you need to be testing in order to
get an accurate picture of your ketone levels. Let’s get started Hey Carbdodgers! My name is Dr. Dan
Maggs thanks for visiting my channel where I help people achieve long-term
sustainable weight loss through low carb real food nutrition. I struggle with my
weight pretty much my entire life until about 2016 when I went from officially obese to a normal way, in just over six months and I’ve maintained it ever since.
And I’d love to show you how to do the same. I release new videos here every
Tuesday and I’d love it if you’d subscribe to my channel and hit that
bell to get notified whenever I release a new video. Now I’ve never been a big
tester of ketone levels and when I went through my period of rapid weight loss
back in 2016 I didn’t actually check ketones once. I didn’t need to because I
was consistently losing weight and ultimately that was the goal and there
seems to be this myth in the keto diet world that we should be aiming for
really really high ketone levels all the time and it’s simply not true. In fact, I
think it often leads to an overconsumption of fat and often an
under consumption of protein and I’ve made a separate video that deconstructs
this myth about high ketone levels. And you can check that out by clicking up
here. It’s also linked down below in the description below this video. Now, a lot
of keto websites or YouTube channels are sponsored by the manufacturers of ketone meters. I’m not, so I’m not going to tell you that you should be testing all the
time because it’s simply not true. But testing does have its place and it can
be useful particularly for overcoming problems. Also I know some people who
find testing their ketone levels just really reassuring. It provides some sort
of accountability to the data and they know their on the right track
also if you like me you’re a bit of a data geek and it can be quite fun to
track these things. So, if you are testing then blood ketone readings are by far
the most accurate way to check your ketone levels but whilst the ketone
meters themselves are often relatively cheap, the test strips are still quite
expensive and we don’t want to be wasting them. Testing more often than we need to or testing at times of day when we’re going to be getting a misleading
reading and there are several times during the day when you’re gonna get
falsely low readings. The first time you should avoid testing is first thing in
the morning and that’s due to something called the DAWN EFFECT. Now the dawn
effect is a normal physiological process that happens to all of us. In the early
hours of the morning, there’s a surge in number of hormones, cortisol and
adrenaline and this is part of the body’s normal circadian rhythms. It
promotes the release of glucose into the bloodstream which is just there to help
you prepare for the day ahead. Now a lot of diabetics noticed a spike in their
blood glucose levels at this time of day but non-diabetic shouldn’t actually see
a rise because insulin should be compensating for that rise in blood
glucose but that rise in blood glucose will also cause a reactionary lowering
of the ketone levels. So, if you testing in the early hours of the morning and
you find that you’ve got a low ketone levels it’s due to the dawn effect you
want to be waiting at least an hour after you wake up as a minimum before
you start testing your ketone levels. The second time you should avoid testing is directly after a meal. Even a low carb meal will cause some insulin to be
released by the pancreas so it’s not uncommon to see a temporary dip in blood ketone levels at that point. Now ketones will often quickly recover over the next
few hours but not in an entirely predictable way and it will vary
depending on the meal. Now as a side note some people do like to see the response
their meals have on their ketone levels and may
like to test on a schedule such as before a meal 30 minutes after that meal
an hour after that meal or 2 hours after that meal just to see what their
response has been and this can be quite interesting for a day to eat like me to
see my body’s response to certain meals but it really doesn’t tell us a lot
about the long-term stable levels of ketones that our bodies are achieving. So
by all means do it if you’re curious but not really for any other reason than
that. Talking of curiosity, I’m curious as to how many people out there are data
geeks like I am. So if that is you and you enjoy testing in that way hit the
like button below and type the word geek in the comments just to let me know. Now
the third time of day you should avoid testing is after exercise. Now ketones
are being used by the body for energy and anything that causes them to be used
faster such as exercise will cause a temporary lowering of ketone levels that
misrepresents your longer-term levels again by all means test for curiosity
but don’t get misled when the levels drop after exercise so that’s when we
shouldn’t be testing but when should we be testing and how often?
Now I typically recommend the best time of day to test is before your main meals
so lunch and dinner, for me. Now that’s typically 12:00 p.m. and 7:00 p.m. which
fits in with my normal 16 8 pattern of fasting checking before lunch gives
plenty of time for that dawn effect phenomenon to pass and typically I
usually work out in the mornings too. Now, if you typically skip breakfast like a
lot of lowcarbers who do intermittent fasting do then it’ll have been
approximately 16 hours since your last meal if you’ve not achieved a stable
level of ketones by this time you’re probably not in ketosis and if I had to
just test once a day it would definitely be this before lunch
check and the check before dinner gives plenty of time for you to achieve a
stable level of ketones after your lunch but not if you’ve just exercised you may
wish to consider testing before bed for example if you often workout before your
evening meal and twice a day we’ll give you a good idea of things are stable
adding in a third testing point I don’t really think it really adds much to your
data. So twice a day is what I usually recommend and if you’re going to be
testing on a regular basis you’re gonna want to find a pattern that works for
your particular lifestyle and stick with it. Just make sure you avoid the common
mistake times that I’ve mentioned above work out what works for you and stick
with it every day. Now be sure to check out my video where I discuss optimum
ketone levels for weight loss please don’t get caught in that trap of chasing
hi ketone levels it doesn’t matter anywhere near as much as you might think
you also might find it useful to check my video which was all about monitoring
the symptoms of ketosis to check you’re on the right lines I’ll put the links to
both of those videos down in the resources section which you can find in
the description of this video. So that’s it for today’s video, I hope you’ve
enjoyed that I hope it’s been useful for you and hope you’ve got something out of
that. If you’ve enjoyed this video, please hit the like button down below and why
not leave me a comment in the comment section
I post new videos every Tuesday so if you want to receive those videos
subscribe to my channel and you can hit the bell if you want to get notified
when those new videos come out otherwise I’ll see you next Tuesday.
Thanks for watching!

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  • Reply Vicky Jackson February 26, 2019 at 11:22 am

    Brilliant again!! Thank you!

  • Reply Dover February 26, 2019 at 1:41 pm

    Haha, data geek here! Although I do love data, I wish I could have seen your VERY clear & practical advice when I first began my therapeutic ketosis experiment. After testing at different times of the day,, I can confirm your recommendations. I settled on your exact suggestions (2 tests each day and the times he said)

  • Reply The Restart Specialist February 26, 2019 at 4:19 pm

    Such a great video. my husband does not want to start any testing just based on the cost. Do you have to do it?

  • Reply Lama Jigme Gyatso: Meditate Like a Jedi February 27, 2019 at 1:28 am

    good tip

  • Reply Ruth Kudzi Coaching February 27, 2019 at 2:11 am

    You make medical topics easy to understand and 'not scary'. Thanks for sharing your expertise with all of us. 🙂

  • Reply Nesting Dolls Realty - Living in Asheville NC February 27, 2019 at 4:37 pm

    Wow, I've never even hear of this. Thanks for great info!

  • Reply InspiredArtDolls February 27, 2019 at 5:15 pm

    Great video! Good tips, I learned more about the keto diet. 🙂

  • Reply Restaurant Shortcut February 27, 2019 at 6:05 pm

    This was very detailed and let me tell you, it's very valuable to know what to test, when to test and how to test. I also appreciate you sharing your schedule with testing your blood ketones. Thanks!

  • Reply Banjo790 Ange February 27, 2019 at 8:05 pm

    Great advice and info again Dr Dan. I’m still debating testing as I’d like faster weight loss but I’m adverse to testing blood ketones, but of needle phobia!!!

  • Reply Pregnancy and Postpartum TV February 27, 2019 at 10:59 pm

    Amazing video! Really clear and helpful 🙂 yes… data geek here as well 🙌 They are $1 a piece here in Canada. Subbed and hit the bell. Looking forward to more of your content!

  • Reply BWoodPhotography February 28, 2019 at 3:27 pm

    Very informative and easy to understand.

  • Reply ArdelleVision March 1, 2019 at 1:45 am

    I never knew any of this information on the importance of when to test for ketones. Amazing video!

  • Reply Chessa Kali March 6, 2019 at 10:30 pm

    Great information! I want to start keto so this was helpful!

  • Reply Chris Hale April 1, 2019 at 3:19 pm

    Yep Geek 🙂

  • Reply Northern Illinois Sasquatch Researchers May 10, 2019 at 10:21 pm


  • Reply TheGhost Behind You May 11, 2019 at 12:56 pm


  • Reply T.M.S Asphalt Maintenance May 28, 2019 at 7:11 pm


  • Reply Debbie Phillips June 4, 2019 at 2:23 am


  • Reply Lazita Laz June 12, 2019 at 6:31 pm


  • Reply Tomika Cannon June 14, 2019 at 2:17 am


  • Reply Salccc1 June 17, 2019 at 10:12 pm


  • Reply Szabo Zsombor June 19, 2019 at 8:06 pm

    Yo dawwwg, fellow geek here. Your content is very good, I'm rooting for your channel to grow!

  • Reply Theresa w June 23, 2019 at 9:09 pm

    I test before I break my fast my readings are constant.

  • Reply Kathryn Ludwig July 26, 2019 at 8:51 pm

    Geek for sure!

  • Reply Linda's World July 30, 2019 at 6:29 pm

    I had been testing my ketones when I wake up – thanks for the tip. Can you tell my if synthroid will have any effect on my ketone reading or insulin?

  • Reply Jeff Lane July 31, 2019 at 7:51 pm


  • Reply vw_vonda August 6, 2019 at 12:23 am

    Total data geek here!!!! 🙋‍♀️

  • Reply cate edwards August 9, 2019 at 11:44 pm

    Helpful !

  • Reply Rhoda Prayer August 15, 2019 at 2:52 am


  • Reply David Lanteigne August 15, 2019 at 11:28 pm


  • Reply Janet Waterfall August 21, 2019 at 8:19 pm


  • Reply elesha burgess August 25, 2019 at 1:10 am


  • Reply Kathryn Bustamante August 31, 2019 at 1:24 am


  • Reply Dol l September 13, 2019 at 7:36 pm

    Total GEEK 👍

  • Reply Jessinta Re September 16, 2019 at 10:21 am

    Geek here

  • Reply Timothy Skover September 19, 2019 at 8:31 pm

    Dr Dan
    This was really helpful. I will now test just before lunch and before dinner. Been stumped by the dawn effect as I would test just at get up and was extraordinarily hi ( sometimes 120) what?? but the later measurement is between 86 and 100 so it does drop. You've got incredible insight to this process especially looking at used ketones that cannot be measured. All the best keep doging those carbs

  • Reply Sinmaan September 30, 2019 at 4:32 pm

    Data Geek here!

  • Reply Dee Ann October 1, 2019 at 6:38 am


  • Reply David M October 9, 2019 at 9:37 pm


  • Reply tdreamgmail October 13, 2019 at 8:59 pm

    Tested for the first time at 8:50pm because I didn't know what I was doing! 0.6 mmol, yeah baby!

  • Reply LG October 18, 2019 at 9:36 pm


  • Reply Teree Gomez October 19, 2019 at 2:16 pm


  • Reply Vera Bendall October 24, 2019 at 1:40 pm

    Great information! Thanks!👍🏻👍🏻👍🏻

  • Reply Yasmeen-Jalilah October 26, 2019 at 2:57 am


  • Reply RL Shultz October 28, 2019 at 7:12 am

    I am a avid cyclist on keto for 4 months. Today I measured before a 50 mile 3 hour ride =92/.7 and then a few hours after = 65 / 1.5. Seems a very positive result.

  • Reply Susan Simpson October 31, 2019 at 4:33 am

    Geek! I’m super carb-sensitive so testing after a meal (or day) of adding carbs shows me which carbs to avoid. 🙂

  • Reply Pamela Kefalas November 5, 2019 at 8:46 am


  • Reply WizardNumberNext November 7, 2019 at 5:26 pm

    I used to run in the morning
    I was testing ketones before run and after I came back home.
    I do not leave house and run right away, but I walk for around 7 minutes, run for 25-30 minutes and then walk back for around 5-6 minutes (I walk faster, as my body is already in higher performance state)
    It my ketone level fall, if liver stays absolutely fine, but they will go up if I get pain because of overworked liver due to ketone production for physical activity)

    Test yourself. Run long enough to trigger sharp pain in liver. It does need to be very painful, just sharp. When you get this you should gradually slow down and get rest of at least just walk. It will pass and it is perfectly fine. It is just signal that liver is working harder and it grows to accommodate extra body needs.

  • Reply WizardNumberNext November 7, 2019 at 5:34 pm

    You are absolutely right
    High ketone level does have no benefit
    Even worse, too high ketone levels may be a sign you are doing something wrong or going downhill
    I used to get even 7mmol/l ketones
    It wasn't my best time to be honest
    Now I am back around 1.5mmol/l to 4.5mmol/l
    Test your ketones and glucose if you get dizzy. You may see unusually high ketone levels and unusually low glucose level.

    You need to have both testers, perfectly as single device. Testing just ketones is less then half picture.

  • Reply WizardNumberNext November 7, 2019 at 5:40 pm

    Retired data geek here.
    I consider subscribing.
    You make quality videos and earning consideration from me is a lot, especially on first day.
    I have watching some channels for 3 years before subscribing.
    I have few objections here and there, but most people simply do not know this stuff anyway, so it is not your fault (faulty science forgetting facts from history).
    Nothing directly related to subject of your channel though.

  • Reply Lucia Seacreature November 18, 2019 at 4:41 am

    my glucose never seem to change whether in am or after a meal (always around 80-90s) but ketones are highest in am and lower in evening… and i only check once a week or every other week

  • Reply Cheryl Peterson November 19, 2019 at 7:57 pm

    Geek…but one who doesn't want to waste money.

  • Reply Cassie Oz November 21, 2019 at 2:14 am

    I've used GKI as an indicator of how I'm travelling (and I'm in it for more tham weight loss)

  • Reply machomp 123 November 24, 2019 at 10:07 am


  • Reply Eric Nagler November 28, 2019 at 11:21 am


  • Reply Steve Ruttle December 8, 2019 at 2:21 pm

    The more data the better.

  • Reply Lisa December 9, 2019 at 2:31 pm


  • Reply Mark Trent December 15, 2019 at 12:37 am


  • Reply Amie Rikke December 29, 2019 at 11:33 am

    Geek! I’m learning lots from your videos!

  • Reply Sue Warnes January 7, 2020 at 10:01 am

    Thank you Dr. Subscribed.

  • Reply Mishelle Jenkins January 9, 2020 at 12:45 am

    Geek 😊

  • Reply Niki Mize January 14, 2020 at 5:12 am


  • Reply fourftr January 15, 2020 at 3:30 pm

    Wow a Dr that actually reply. I’m impressed

  • Reply Liam Kelly January 17, 2020 at 12:36 pm

    What's the cheapest and a selection of different products that test ketones and diabetes levels? It's a bit of an expensive minefield and when you read some comments of products, they're very varied and not always complementary. I look forward to hearing from you.
    Kind regards

  • Reply jwarrenfeltz72 January 21, 2020 at 11:59 pm

    Super Geek here. Garmin, HR monitor, keto mojo meters for ketones and glucose… even a meter on my tennis racket to tell me what's going on. 🤓

  • Reply Joni Larsen-Haikarainen January 22, 2020 at 1:54 pm

    I have been testing my ketone levels before and after (high intensity) exercise out of curiosity. So far I have noticed a very strong correlation between high ketone levels before exercise and better performance.

  • Reply Donald Moore January 24, 2020 at 7:21 pm


  • Reply Hobby_Gardener412 January 24, 2020 at 8:10 pm

    I just bought a blood ketone meter and this video was so helpful! I didn’t know if you were supposed to check ketones like you check blood glucose levels, when, how often, etc… As an RN I’ve only ever checked people’s blood glucose levels. Ketone levels and the normal ranges are a whole new thing for me. Love your channel. So glad I found it!! Thank you for all your valuable knowledge on the ketogenic diet!!!

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