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Is Coffee OK During Intermittent Fasting?

Intermittent fasting (IF) is a modified eating approach that seeks to replicate the benefits of fasting but with a more moderate and achievable protocol.  IF benefits more than just your waistline; it also helps to stabilize blood sugar levels, reduce inflammation and keep your heart healthy.

So is coffee OK during intermittent fasting? The answer is, that it depends.

It actually depends on why the person is doing intermittent fasting. What are their goals? Are they doing it for weight loss or more for longevity and anti-aging purposes?

One basic question is what do they mean by coffee – just black coffee or bulletproof coffee, which often has butter, coconut oil and/or MCT oil. I think that bulletproof coffee is probably NOT a good idea for either goal, because of the high calorie count.

If someone is primarily doing it for weight loss, then plain black coffee, which has 0 calories, is fine. In fact, the appetite suppressing effects of coffee are probably beneficial.

If someone is doing IF more for anti-aging purposes then coffee is probably not a good idea. The reason is that even black coffee disrupts the process of autophagy which is the main way that intermittent fasting promotes longevity.

Autophagy is the self cleaning process by which the body’s cells break down and recycle damaged proteins and components. This is activated by intermittent fasting, but anything other than water (even black coffee) disrupts it to some extent. Autophagy is a very important process that was elucidated recently in research that was awarded the Nobel Prize in medicine.

The final caveat is that some fasting is better than none. So if having a regular or even bulletproof coffee is the only way that you can stick with the practice of intermittent fasting, then it’s probably worth it. What’s been your experience with coffee and intermittent fasting? Please share in comments below.



  1. Shea April 18, 2018 at 10:41 am - Reply

    I am practicing fasting for weight loss and anti-aging. I am hoping the autophagy helps with loose skin. I switched from BPC, to black coffee with Erythritol. I noticed my blood sugar spiking after consumption, so I switched the black coffee. This was huge for me. Unfortunately my blood sugar is STILL spiking 20-30pts after drinking black coffee. I am not diabetic, but I am insulin resistant.

  2. Holly May 11, 2018 at 1:58 pm - Reply

    I too have spikes with coffee. I do fatty tea in the am. I have experienced a calmer demeanor and less hot flashes. After eliminating coffee and switching to tea I did an experiment and added it back several days later, I felt horrible. It kind of clouded my head and gave me a stomach ache. Go Figure!

  3. Sandra Ruiz Prudencio June 8, 2018 at 5:54 am - Reply

    I have a question: Even green tea or Rooibos would disrupt it? I´ve been practising IF (16/8) for 2 years but I stick really good with black coffee.

    • oskyadmin June 14, 2018 at 9:54 am - Reply

      If the coffee helps you practice IF then stick with it!

  4. Daniel Barras July 18, 2018 at 11:26 am - Reply

    Studies show exactly the opposite effect from coffee. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4111762/

    • oskyadmin July 22, 2018 at 6:10 pm - Reply

      interesting study with animals – hope we get more human data soon – thank you for sharing!

    • Shawn Kelly July 27, 2018 at 5:04 pm - Reply

      Thank you for posting the study link . Seems the whole coffee stopping autotphagy may just be so oft repeated that people are mistaking it for a fact.

  5. Vineeth Sastry August 8, 2018 at 3:28 am - Reply

    Sir, the question I cannot find an answer to is can I add sugar to my coffee and if so how much? Thank you

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