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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11 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

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