Why do ketone levels vary throughout the day?

By Dr. Stephen Phinney and the Virta Team

Individuals vary in their blood ketone levels (i.e., beta-hydroxybutyrate – aka BOHB) over the course of a day and from day to day. This can be due to variations in dietary carbohydrate and protein from meal to meal and from day to day.

However, different individuals tend to vary in the levels and pattern of their blood ketones. Some people are highest in the morning and tend to have reduced levels after meals (perhaps due to the dietary protein and carbs they consume). Others of us tend to be low in the morning and then rise during the day.

Additional factors that increase blood BOHB are endurance exercise and also after consuming fats containing medium chain triglycerides (MCT) such as butter, coconut oil, or purified MCT oil. In contrast, there is often a steep drop in BOHB after high intensity exercise, the mechanism for which has yet to be proven. This post-sprint drop in BOHB tends to be temporary (lasting for an hour or two), which means that it’s cause is very different from the days-long drop in blood BOHB that one sees after a large carb meal.

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28 Comments

  1. Avatar
    Frank Rogers, PhD March 4, 2019 at 5:34 pm

    Any citations you know of with multi-day ketone curves? Observing that patterns vary among individuals, likely due to many underlying effects (age, gender, nutrition, &tc), I am curious whether any work has been undertaken to systematically record and analyze patterns across subjects, either in your own trials. There are some interesting reports of blood glucose patterns in ketogenic subjects (Virta’s work, of course, included). Any BHOB time-series data on ketogenic subjects?

    -Frank

    Reply

    1. Virta Health

      Unfortunately, we aren’t aware of any published data that directly addresses that question.

      Reply

  2. Avatar

    Not sure that canola oil is a healthy fat

    Reply

    1. Virta Health

      You may find Dr. Phinney’s take on canola oil helpful for understanding why it is used with our patients: https://blog.virtahealth.com/canola-oil-keto/

      Reply

  3. Avatar

    Is there any information that shows the relationship between measurements of urine ketones and blood ketones? For example, if the urine results are moderate, say 40 mg/dL = 4 mmol/L, should the blood level reading also be 4 mmol/L ? What does it mean if the actual simultaneous blood reading is only .4 mmol/L?

    Reply

    1. Virta Health

      There is great variability between urine and blood ketones. One of the reasons for this is due to hydration. The better hydrated you are, the more dilute your urine will be and this will cause urine ketones to drop. If you are dehydrated, urine ketones will appear higher than your actual blood ketones will measure. We recommend using blood ketones whenever possible in order to eliminate the guessing game that comes with urine ketones.

      Reply

    2. Avatar

      urine good be in the bladder up to 6 or 8 hours or more. There for not as accurate as in the blood which is real time.

      Reply

  4. Avatar

    I just ate a very high fat meal (which also contained protein and carbs in alignment with my Keto macros). Thirty minutes later my blood ketones have risen from .7 to 1.2. Is that just my body converting the fat in the food I just ate to ketones? If so, how does that help? I want to use my own fat to make ketones. Thank you!

    Reply

    1. Virta Health

      What you eat can definitely impact your blood ketones, however it doesn’t mean that your body is only using the fat from your meal. It just means your meal was well balanced and supported ketone production. If your goal is weight loss, the best measurement is going to be monitoring your weight over time. If you are eating too much and limiting the amount of fat your body is burning from stores, then you won’t see the scale move.

      Reply

  5. Avatar

    Besides noting that my levels drop after an intense workout, I have also recently noted that they drop greatly while sleeping!

    For example, Friday bedtime I was 1.2, but I awoke in the morning at 0.3. Saturday bedtime was 0.9 and awoke today at 0.5. I had been given to understand that the prolonged fasting (I also use time-restricted eating) overnight is supposed to increase ketones.

    I seem to be missing something here

    Reply

    1. Virta Health

      Thank you for your question, Rick! That may be due to dawn phenomenon and increasing blood sugar levels. As blood sugar rises, ketones can be suppressed. You can read more about the dawn phenomenon here: https://blog.virtahealth.com/dawn-phenomenon/

      Reply

      1. Avatar

        What if I have been monitoring my glucose and ketones for months and they ranged from 0.5-0.9 in the morning with sugar levels at 85-89. Now in the past 2 weeks my sugars are now 0.2-0.5 in the mornings and sugars are 97-112. I have been keto for almost a year and have changed nothing in my routine or eating. Can dawn phenomenon start to occur after not experiencing it initially? I just don’t know what I am doing wrong.

        Reply

        1. Virta Health

          There are many variables that could be contributing to a change in your blood sugar and ketone levels. Stress, inflammation, poor sleep, etc can all impact your biomarkers and may be the culprit. You may also want to look and see if any of your regular food items have changed and now have additional carbs.

          Reply

  6. Avatar
    Dominic Iagrossi Sr July 7, 2019 at 2:03 pm

    I am a type 2 diabetic and concerned about ketones. My bg readings average around 140 throughout the day. I eat plenty of carbs around 200g a day and still show ketones in my blood everyday. I average around .6 readings. My biggest concern is working out with ketones. I was told not to workout when I show ketones readings. Any advice??

    Reply

    1. Virta Health

      We are unable to provide medical advice in this forum, so we would recommend that you speak with your physician.

      Reply

  7. Avatar

    How does strength training (anaerobic) workouts affect the ketone levels? I have been doing quite well—in ketosis —but did a heavy duty strength training workout Sunday evening awaking to a ketone level 0.2 1 1/2 hours after waking—never had this happen before. My ketones did rise to 0.9 by the end of the day—I am training for a marathon, too

    Reply

    1. Virta Health

      Hi Nancy! Great question! Strength training and high intensity workouts are known to transiently drop ketone levels, however the mechanism for why this happens isn’t totally clear.

      Reply

  8. Avatar
    Dennis Paidley July 29, 2019 at 7:12 am

    My daughter suffers from Glut 1 Deficiency Syndrome and has been on Keto for approximately 10months to treat the condition. She is 10yr old and is 100% diet compliant, but her Keytones can fluctuate from .8 to 2.2 in a 24hr period and then other days be perfectly fine for the entire day whilst eating the same meals.

    What other factors outside of diet can have these kind of effects on her levels? Exercise obviously, but what about sleep patterns or anything like that?

    Reply

    1. Virta Health

      Hi Dennis! Things like stress, inflammation, poor sleep, and illness can all effect blood sugar and blood ketone levels. We would encourage you to speak with her healthcare team if you have concerns.

      Reply

  9. Avatar

    I am following a ketogenic diet (breakfast 80%, lunch 75%, dinner 90% by energy value) and initially ketones were around the 1 mark, about a month later and they seem to hover around the 0.3 mark.
    I am a type 1 diabetic and my blood sugar values have also increased somewhat (was averaging 5.6 mmol/l, now around the 6.2 mmol/l mark)
    Any thoughts?

    Reply

    1. Virta Health

      Hi Mark! I’m sorry but we are unable to provide specific medical advice via this forum. We’d recommend connecting with a healthcare provider who can work with you to meet your goals.

      Reply

  10. Avatar

    After a 16 hour fast, my glucose was 83 and ketones 2.3. I had my meal after the fast about 3 hours later my I tested my glucose and ketones. They were 93 and 1.5, respectively. Would this be an indicator that the food I had to eat is not the best for my body?

    Reply

    1. Virta Health

      There are many variables that go into how your blood sugar or ketones respond, but if you consumed carbohydrates in your meal, we would expect your blood sugar to rise and wouldn’t be surprised to see ketones drop slightly. We consider anything over 0.5 mmol/L to be ketosis, so you would still be in range.

      Reply

  11. Avatar

    Ketones on an avergae at 3 mmol/L in the morningn, then around 2mml/L during he day. Back to 3mml/L before bedtime. Thought they where suppose to be lower in the morning? ( Glucose always below 5mml/L unless i have a treat day. (not seen it above 7 mml/L) ) Thank you.

    Reply

    1. Virta Health

      Although ketones are typically lower in the morning, it will vary from person to person.

      Reply

  12. Avatar

    Can going on a diet cheat day help my metabolism increase?

    Reply

    1. Virta Health

      Hi Anne! There is no literature that I am aware of that demonstrates a cheat day can help improve metabolism. Our patients are encouraged to continue on the Virta treatment daily.

      Reply

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