Intermittent Fasting and Coffee

  • 1st Revision: Tserendumaa Enkh-Amgalan (Dumaa)
  • 2nd Revision: Kaamya Mehta[Linkedin]
  • 3rd Revision: Jasmine Yeh[Linkedin]


What is Intermittent Fasting?

Fasts are generally represented in religion. For example, Muslims fast in the month of Ramadan, Christians will fast in the month of Lent, Hindus will fast during Shravan Mahina, Jains will fast during the festival of Paryushan, etc. In the modern era, fasting has become popularised as a form of a diet for losing weight and staying healthy.

Intermittent fasting involves abstaining from food and certain drinks for a period of time to improve health. These periods can vary in length and structure. Generally, we can categorise intermittent fasting into three main types: complete alternate-day fasting, time-restricted feeding and whole day fasts.1

  • ‘Complete alternate-day fasting’ involves restricting all energy-containing food and drinks on alternate days. 
  • ‘Time-restricted feeding’ allows some energy consumption on fasting days which tend to be held on two days a week, with 16-hour fasting times and an 8-hour break. This fasting regimen is known as the 5:2 diet and has gained popularity due to its reported health benefits.2
  • ‘Circadian fasting’ is based on eating during the light hours and fasting in the dark. Our bodies have a biological clock, also known as a ‘circadian rhythm’, which allows processes in our body to occur at certain times during the day or night, according to when our bodies work best. It is thought that our feeding times help control our natural body clock, which is why the times we eat can play an essential role in our overall health.2

What are the Benefits of Intermittent Fasting?

Circadian Rhythm Function

Insulin is an example of a hormone that follows a circadian rhythm, whereby insulin sensitivity decreases throughout the day and into the night. Insulin is a hormone secreted by the pancreas. When our pancreas secretes insulin, it acts as a messenger to the cells in our body to take in sugar (i.e. glucose) from our blood. Our cells then use glucose as a vital energy source or store it as glycogen, ready to be used when needed.3 

Intermittent fasting can help the body to rest and recover, improve gut function and help the body to become in sync with its circadian rhythm. For example, late-night snacking causes a rise in insulin and the release of energy when at that time, the body is more suited to be in a rested state to optimise recovery.


Metabolism is a process that describes a series of chemical reactions in the body, which break down food into energy. Intermittent fasting is known to increase metabolism, and instead of relying on glucose as an energy source, it uses ketones stored in fat to fuel the brain and body. In this state, the body has undergone ketosis and is called keto-adapted. Ketogenesis is the critical mechanism in intermittent fasting by which weight loss is achieved.1 

When there are increased levels of ketones in the body through ketogenesis, they not only serve as a fuel for the body, but also have effects on other functions. For example, they help trigger the repair of the damaged molecules in the body, and can reduce inflammation and improve glucose regulation.4

Intermittent fasting can help lower blood glucose levels and insulin levels, which overall means that it can help prevent type II diabetes.

Blood pressure

Intermittent fasting has also been shown to lower blood pressure, exerting less stress on the heart, and in turn decreasing the chances of developing cardiovascular disease.

Weight Loss

Fasting is excellent for weight loss. Several factors can lead to obesity, including genetics, medications, stress, and several medical conditions. One largely modifiable cause is a high-calorie intake. Studies have shown that even a 1-day fast can reduce calorie intake over the next three non-fasting days by around 30%.2

In particular, fasting has been shown to decrease visceral fat, which is fat that is concentrated in the ‘deep belly’ and wraps around essential organs, such as the liver and intestines. As this fat is deep within the body, it isn’t always noticeable, and high levels can be present even if your stomach is relatively flat. High levels of visceral fat is a risk factor for type II diabetes. 

Cognitive Function

Some studies have shown that intermittent fasting can improve cognitive brain function and activate a process called ‘autophagy’, which describes the cleaning of cells and removal of unwanted or damaged cells. This has been considered crucial for brain function, and impaired autophagy has been linked to neurological disorders, such as Parkinson’s disease and Alzheimer’s.5


Cancer is one of the leading causes of death worldwide. The causes of cancer are complex and vary depending on the type of cancer. However, many types can be prevented with lifestyle changes. Studies have shown that intermittent fasting has anti-inflammatory effects and can prevent tumour growth.1

Can I drink coffee during Intermittent Fasting?

Yes! Great news for coffee lovers - coffee can be drunk during intermittent fasting, and is even known to share similar health benefits, such as helping with weight loss and triggering autophagy. As intermittent fasting aims to detoxify the body, choosing organic coffee is preferable. Coffee lovers should consider drinking this beverage during a fast, as it may help keep to the fasting lifestyle.6 

It should also be noted that those who suffer from irritable bowel syndrome (IBS) or any other kind of gut-related health issue should unfortunately avoid drinking coffee on an empty stomach, as this has been linked to worsening of the condition.13

Benefits of Coffee during Intermittent Fasting

Reduced Inflammation

Coffee can help reduce inflammation, an excellent protective effect since inflammation is a hallmark of many conditions, such as cardiovascular disease, type II diabetes, and cancer. One component in particular in coffee, called chlorogenic acid, is thought to contribute to coffee’s anti-inflammatory effects.7

Boosted Metabolism

Coffee is regarded as a natural stimulant and, as such, can help improve metabolism. This means the number of calories you burn in a day will increase and lead to weight loss. 

Better Brain Health

Coffee does not only contain caffeine, but it also has many other compounds that, when consumed, can improve health. Studies suggest that coffee has been linked to a reduced risk of neurodegenerative disorders, such as Parkinson’s disease and Alzheimer’s.8 However, like the majority of good things, coffee should be taken in moderation as excess caffeine is linked to migraines, anxiety, insomnia, etc.14 In order to avoid this, try drinking more decaffeinated coffee.

Increased Autophagy

We already know that intermittent fasting can lead to autophagy; however, drinking coffee, whether caffeinated or decaffeinated, can help trigger the process further and boost its anti-inflammatory and cell cleaning effects on the body.6

Can adding ingredients to my coffee reduce the benefits of fasting?

Generally, you should be careful when considering adding ingredients to your coffee, as some additions may contribute to breaking the fast. Black coffee is believed to have virtually no calories, so the coffee does not violate an intermittent fast. However, adding calorie-containing products, such as milk or sugar, may cause you to break the fast.6

If you find black coffee too strong or aren’t used to its bitter taste, add a healthy fat, such as unsweetened almond milk, to make it more palatable. Using a no-calorie natural sweetener may also be an excellent option to counteract the bitter taste. 

What can I add to my coffee that won't break my fast?


Nutmeg can be added for flavouring and has excellent health benefits as it is rich in antioxidants. Antioxidants are substances that prevent damage to cells. As such, nutmeg is great for its anti-ageing properties and for helping to prevent severe conditions, such as cancer and heart disease. 


Cocoa contains a stimulant called ’theobromine’, which helps boost metabolism. Adding a good quality dark chocolate, high in fat and low in sugar, is a good option.10


Cinnamon is a warming spice that provides flavour and has health benefits. It has anti-inflammatory properties, can reduce the risk of heart disease and can help fight bacterial infections. Cinnamon can also improve insulin sensitivity, which means that cells are more likely to take in sugar from the blood, reducing blood sugar levels and helping to prevent metabolic disorders such as type II diabetes.11

Almond Milk

It is best to use unsweetened almond milk as it contains fewer calories and has only natural sugars. Almond milk has fewer calories than regular cow’s milk and serves as a good source of calcium. 

Coconut Oil

Bulletproof coffee is made from coffee, MCT oil or coconut oil and ghee. These high-fat, low-sugar ingredients are perfect for intermittent fasting as they do not raise insulin levels. MCT stands for medium-chain triglycerides, a fat whose shorter chain length means they are easy to digest. Coconut oil is known to contain MCT naturally. MCT alone has outstanding health benefits, such as aiding weight loss, helping you to feel fuller for longer, and improving gut health.12 Ghee is a form of clarified butter. It is made by simmering butter and removing the milk solids, which come to the surface.  

What are the risks of drinking coffee whilst fasting?

Careful consideration should be taken, as too much coffee, or coffee consumed at the wrong time, can lead to anxiety and sleep disturbances and can worsen symptoms for people suffering from gastro-oesophageal reflux diseases, such as reflux and heartburn. Generally, between 3 to 4 cups (~ 300 to 400 mg of caffeine) of coffee a day is fine to drink.6


Intermittent fasting is a lifestyle choice that can prove beneficial to many individuals. Both diet and exercise play a crucial role in maintaining good physical and mental health. Some of the best and most meaningful lifestyle choices are realistic and sustainable, so the 5:2 diet holds excellent popularity and success. It is relatively easy to maintain over a long period and more manageable to adopt than a steady calorie reduction diet, which requires a constant counting of calories.3


  1. Visioli F, Mucignat-Caretta C, Anile F, Panaite SA. Traditional and medical applications of fasting. Nutrients [Internet]. 2022 Jan 19 [cited 2022 May 29];14(3):433. Available from:
  2.  Patterson RE, Sears DD. Metabolic effects of intermittent fasting. Annu Rev Nutr [Internet]. 2017 Aug 21 [cited 2022 May 29];37(1):371–93. Available from:
  3. Kim BH, Joo Y, Kim MS, Choe HK, Tong Q, Kwon O. Effects of intermittent fasting on the circulating levels and circadian rhythms of hormones. Endocrinol Metab [Internet]. 2021 Aug 31 [cited 2022 May 29];36(4):745–56. Available from:
  4. Research on intermittent fasting shows health benefits [Internet]. National Institute on Ageing. [cited 2022 May 30]. Available from:
  5. Autophagy: Scientists discover novel role for self-recycling process in the brain [Internet]. ScienceDaily. [cited 2022 May 29]. Available from:
  6. Can you drink coffee while intermittent fasting? - wefast [Internet]. [cited 2022 May 30]. Available from:
  7.  Coffee GR. Does coffee cause inflammation? [Internet]. Golden Ratio Coffee. [cited 2022 May 30]. Available from:
  8. Socała K, Szopa A, Serefko A, Poleszak E, Wlaź P. Neuroprotective effects of coffee bioactive compounds: a review. IJMS [Internet]. 2020 Dec 24 [cited 2022 May 30];22(1):107. Available from:]
  9. Sarriá B, Sierra-Cinos JL, García-Diz L, Martínez-López S, Mateos R, Bravo-Clemente L. Green/roasted coffee may reduce cardiovascular risk in hypercholesterolemic subjects by decreasing body weight, abdominal adiposity and blood pressure. Foods [Internet]. 2020 Aug 28 [cited 2022 May 30];9(9):1191. Available from: 
  10. Can coffee increase your metabolism and help you burn fat? [Internet]. Healthline. 2018 [cited 2022 May 30]. Available from:   
  11. 10 evidence-based health benefits of cinnamon [Internet]. Healthline. 2018 [cited 2022 May 30]. Available from:
  12. 7 science-based benefits of mct oil [Internet]. Healthline. 2020 [cited 2022 May 30]. Available from:
  13. Ersoy A. Should you drink coffee on an empty stomach? [Internet]. HuffPost. 2017 [cited 2022 Jun 27]. Available from:
  14. Spritzler F. 9 side effects of too much caffeine [Internet]. Healthline. 2017 [cited 2022 Jun 27]. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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