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.
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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.
The caffeine in coffee is a stimulant which normally cause a spike in insulin…. that may be why you blood sugar is spiking.
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!
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.
If the coffee helps you practice IF then stick with it!
I find having my regular coffee with cream and a little sugar satisfies me so much that I can go 20-24 hours without eating on IF and I am good. When I break my fast it’s usually with a high protein meal with no more than 10g or fat. I have lost weight and I have lost fat 😊
Studies show exactly the opposite effect from coffee. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4111762/
interesting study with animals – hope we get more human data soon – thank you for sharing!
Hello oskyadmin. We agree that studies with mice do not prove results (caffeine inducing autophagy) will be the same with humans. Yet it’s a good start to believe it will, when we see how efficient it is with mice on many organs (liver, heart, muscle..). But in your article you affirm the opposite as a fact : “even black coffee disrupts the process of autophagy”. Can you please name your sources ??? Thank you.
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.
This study is not showing the opposite effect, because the study does not look at the effect of coffee while fasting. They are not looking at the same scenario. Perhaps other studies have been made on this scenario, but I’ve not found one yet.
Daniel, this study does not show the opposite effect, because it is not looking at coffee consumption while also fasting. Fasting is not addressed at all in that study, and coffee consumption while intermittent fasting is what this article is addressing.
There are no sources to support his statement. Rank conjecture and irresponsible.
Sir, the question I cannot find an answer to is can I add sugar to my coffee and if so how much? Thank you
no to sugar , only very small amount of milk or cream is acceptable. however i’ve watched this interesting youtube video
https://youtu.be/m6KClPkotxM?t=441
I’m no expert but adding sugar likely detracts from IF and would be considered breaking the fast window.
Do not add sugar if you are fasting.
No sugar or creamer. Just black coffee, plain green tea, and water. That’s it during fasting period
> even black coffee disrupts the process of autophagy
Sir, do you have any references to research studies about this?
Hello Sir, we agree that studies on animals do not prove the same results on humans. This being said, when we see how efficient it is on mice (caffeine inducing autophagy very quickly on liver, heart, muscle..) we can be confident for humans that at least it will not have negative effects. But you affirm the opposite : “even black coffee disrupts the process of autophagy”. Can you please name your sources ?? Thank you.
None of the comments on coffee stopping autophagy are in anyway supported by peer reviewed research. There is no evidence whatsoever to support the theory that black coffee has any negative effect on water fasting. If anything the opposite is true.
This so called “Dr. Akil” didn’t reply – he gives misinformation here that conflicts with published science. Black coffee induces autophagy, it doesn’t stop it. When another commenter gave the link to the study, “Dr. Akil” didn’t reply. Misinfo all over the internet by these quacks.
You say coffee stops autophagy: where is the research to prove that? Everything I’ve read says the exact opposite. Here is one such research/study:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4111762/
I started Autophagy 16/8 hours .In the period of 8 hours of eating can I drink coffee?
Yes that should be fine.
In that 16 hours of fasting can one have a black coffe if practising autophagy for weight loss? Please suggest
Yes if the goal is weight loss that will not have a negative impact.
–Dr. Akil
The writer of this article said…” but anything other than water (even black coffee) disrupts it to some extent “…
My understanding to this means black coffee may or may not…
Hi just wanna ask if 12hrs fasting is also ok or best if 16hrs fasting? Another question is it ok after fasting drink black coffee with unsweetened cocoa powder,Stevia and all purpose cream?
Thank you
I’ve read opposite is true on coffee stopping autophagy – I don’t think he has a source. I’m drinking black coffee and matcha green tea. Also mint hope that’s ok.
Hi Dr Akil. I am new to IF and slowly working my way up to a 16 hour fast. I have a question about coffee with heavy whipping cream. I have been having black iced coffee with a tablespoon of heavy whipping cream and then having a 2nd cup usually less than an hour later with the same amount of heavy cream. Since 1 tablespoon of heavy cream contains 50 cal, does having 2 cups that close together break the fast due to the combination of the calories of the heavy whipping cream too quickly together?
probably yes
Looks like coffee is the sacred cow, most people cannot do without it and its addiction is greater than alcohol. Agree that coffee which has caffeine is unhealthful.
I have been doing intermittent fasting for 2 years now, I have not had alcohol in 2 years or caffeine in any shape or form, my energy is balanced througout the day and i can run 4 miles in 28 minutes at 49 years old, the only thing I drink tea wise is red brush tea which is naturally caffeine free, the longest fast I have done was 45 hours anybody done longer ?