Does coffee break a fast?


  • The number of calories in coffee and whether or not it affects a fast.
  • Three most common fasts and the results of drinking coffee while being on them.
  • Adding other ingredients to coffee and the effect it has.


A really common question people ask when doing a fast, that is to say not eating for a period of time, is “can I drink coffee?”. The answer is yes and no. So we want to quickly explain what we mean so you now know! 

Whether coffee is going to break a fast is an important question. In our opinion, as we are into fasting, and are coffee lovers, this question is one that deserves a quick look at the science behind it! 

Because giving up on food for a while is one thing, but also having to give up your favourite morning pick-me-up might be a bit of a deal breaker.

So does coffee breaks your fast? Or can you have your cuppa and sip it, too? 

Read on to find out (hint: it’s mostly good news).


Pouring filter coffee 

So what does “break a fast” mean?

Before we can answer whether or not coffee breaks a fast, we should first define what "breaking a fast" actually means. By definition, fasting is to refrain from consuming food. So breaking a fast would be to start consuming food again after a period of fasting. 

If we’re going to be technical (and we do love a technicality), whether or not something “breaks your fast” depends on three things: 

  • The type of fast you’re doing
  • Your goals with that fast
  • Whether the food/drink may interfere with your fast

Certain types of foods and beverages can unintentionally break your fast while others will have little to no impact at all. It is important to do a fast carefully and understand what foods have an impact before starting. [9]

There are a few different ways that a person can fast. A lot of people practice intermittent fasting to improve body comp as one way of fasting. 


What are the three most common fasts?

Most people fast to improve one, or a combination of, the following:

  • Body composition
  • Longevity 
  • General gut health

Based on the research, we believe the best fast for...

  • Body composition is intermittent fasting (IF) -- This is commonly defined as fasting for 12-22 hours with no food intake.
  • Longevity is the non-caloric liquid fast (NCLF) – This is commonly practising consuming only zero-calorie liquids. 
  • Gut health is the caloric liquid fast (CLF): This is giving your digestive system a break and only consuming calories only in liquids such as bone broth or smoothies.

Now that we have our fasting goals and methods defined, let’s answer the question for each of the three popular fasts:

Clock on plate

Does black coffee break an intermittent fast?

One of the reasons intermittent fasting (IF) has become so popular is its ability to boost metabolic health, support fat loss, and improve body composition. Its effectiveness is likely due to its effect on insulin and blood sugar, a phenomenon Dr Jason Fung has studied for several years

He noted that when we eat, food is broken down into glucose, and therefore the level of glucose in our blood (known as blood sugar) will rise. In response to this, our pancreas releases insulin, which shuttles the blood sugar around your body, and facilitates the update of blood sugar into fat cells. 

However, insulin also stops your body’s ability to use fat (stored body fat obviously included) as a fuel for energy. 

So therefore when insulin levels are high, the body will store glucose in the blood as fat, while also stopping the body’s ability to burn fat, as it instead burns glucose as a fuel source. 

Remember, that this is a perfect way for the body to keep us alive, and it doesn’t care what we look like in the mirror! 

This is one of the ways why intermittent fasting will improve body composition, as short fasts will allow us to burn the body’s stored glucose and utilise our own body fat as fuel. 

Therefore, to interrupt an intermittent fast, something would need to elevate blood sugar and therefore insulin levels! And black coffee does not elevate insulin to a level that will stop your body from burning through stored fat!

Moreover, it would actually be a good thing to drink black coffee in the morning as it increases your ability to burn fat (through higher amounts of fat oxidation) and also suppresses hunger, so you can fast for longer without feeling hungry. [1] . Coffee has also been shown to activate the Nrf2 pathway, a genetic pathway that turns on over 200 genes, many of which are related to detoxification and fat loss [2] .

Please note, that for women, body composition-related results of fasting may vary (especially pre-menopausal women). 


Red cup with coffee and coffee beans

Does black coffee break a non-caloric liquid fast for longevity?

The benefits of coffee on long-term health are well-studied and show promise for daily coffee consumers. 

When people are going through a liquid fast for longevity, they are highly concerned about the process of ‘autophagy’ which is the repair process of all our cells! 

Autophagy is a repairing process where cells “cleanse themselves” by replacing old and damaged parts of cells (proteins) with new ones, and optimising the function of each cell. This process has been associated with anti-ageing and longevity because it keeps cells young, healthy, and functioning as well as they could be.[8]

So, therefore, does black coffee interfere with the process of autophagy? 

No. In fact, a recent study in 2014 has shown that coffee consumption not only doesn’t break a fast, but it may enhance the process of autophagy! This was speculated due to the polyphenols in the coffee. So coffee appears to enhance this type of fast as well! [7]



Does black coffee break a liquid fast (with calories) for gut health?

Fasting can help to improve digestion and gut health as it gives it a little rest, which will boost its resilience against stress, which in turn increased the levels of good bacteria (healthy microbiome), and also kills harmful microbes.[6] When you’re fasting for gut health, you can still consume calories in the form of liquids, such as smoothies and shakes, as they’re easy to digest. Bone broth, juices, and liquids containing nutrients are excellent choices as they are beneficial to your guy microbiome and intestinal lining. 

Once again, coffee actually IMPROVES this kind of fast! Coffee is considered to have beneficial effects on our microbiome! 

However, if you feel any adverse effects from drinking coffee on an empty stomach, such as heartburn or acid reflux, then you may wish to skip the coffee. Or better yet, simply opt for an organic coffee that isn’t heavy in artificial chemicals (as many non-organic ones from cafes, petrol stations, convenience stores and canned coffees are). It is good practice to always look for organic when you are fasting for gut health, as you do not wish to add hundreds of chemicals like pesticides, insecticides, herbicides, fungicides and more into your healthy ritual! These low-quality coffees can leave you with stomach upset, headaches and jitters!

What about coffee with added ingredients?

It comes down to what you wish to add to your coffee of course! A dash of milk? A hint of cinnamon sugar? Does it ruin the fast?  The main idea to consider is what you’re fasting for!!  For example, milk sugars, or honey will elevate blood sugar and therefore break a fast for body composition, but it may not affect a fast for gut health. 

Black coffee

Coffee itself has almost no calories, and some studies have demonstrated numerous health benefits associated with drinking coffee. 

It’s very likely that if you’re fasting for weight loss/metabolic health or longevity then coffee likely does not break your fast! This is because of the zero calories in coffee, and while it will trigger your digestive system, it won’t make a difference to insulin and blood sugar levels. Caution: Fasting is not for everyone, especially those who are pregnant or breastfeeding, under the age of 18, or have diabetes, low blood pressure, or a history of eating disorders. Please consult your doctor before starting a fasting practice.

Final note: If you’re fasting for gut health and to give your body a bit of a “reset” then yes, even a small cup of black coffee will stimulate digestive functions.


Cuddles up with coffee

Most people are fasting for one of three reasons, improving body composition, longevity health benefits and gut health. 

Drinking black coffee actually enhances the benefits of ALL three of the above fasts, so not only should you consider having a coffee, but it’s actually going to improve the fasting benefits! 

However, please be mindful of “poor quality coffee”. As conventionally-grown coffee (both instant, pod form, espresso or barista-made) can contain a host of negative artificial ingredients that you do not want in your body when you are fasting! 

So if you are going to drink coffee during the fast, you are better off going for organic coffee that provides clean energy and high levels of healthy antioxidants, so you don’t have any stomach upset or jitters. 

This is why we have worked so hard at Savvy to source some of the healthiest coffee possible. We support you during your fasts, and every single moment after that too!!



[1] The effect of caffeine on energy balance

[2] Health effects of coffee: Mechanism Unraveled?

[3] Population-bassed metagenomics analysis reveals markers for gut microbiome composition and diversity.

[4] Population-level analysis of gut microbiome variation

[5] The reciprocal interactions between polyphenols and gut microbiota and effects on bioaccessibility

[6] Coffee induces autophagy in vivo

[7] Fasting molecular mechanisms and clinical applications

[8] What breaks a fast? Foods, Drinks and supplements

[9] What breaks an intermittent fast?

[10] When to fast, 3 different types of fasts and their benefits

[11] Can you drink coffee while doing intermittent fasting?