Does Coffee Break A Fast

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Key Information

Coffee does not break a fast

Coffee is a zero-calorie beverage that does not affect insulin levels or disrupt autophagy.

Coffee boosts fasting benefits

Coffee enhances the effects of fasting on metabolism, brain health, aging, and mood.

Coffee should be consumed black

Adding sugar, milk, cream, or other sweeteners to coffee will break the fast and negate its benefits.

Bulletproof coffee may be acceptable

Bulletproof coffee is a high-fat drink that may support ketosis and appetite suppression without breaking the fast.

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When I first began fasting, I made it a point to be strict, water-only faster as I thought this was what fasting was.

However, as I spend more time in biohacking circles and observe what others are doing, I notice many folks drinking coffee during their fasting period.

As a coffee lover myself, I quickly became curious if that was something you could do without breaking your fast.

After digging around the research on how coffee consumption affects a fast, I not only discovered coffee wouldn’t break your fast but that it can actually boost many fasting benefits.

This article dives into the research of coffee’s influence on fasting and helps you decide if you should add it to your routine.

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The Health Benefits Of Drinking Coffee

Coffee is a universal elixir with many uses and benefits.

Whether you drink coffee to get up in the morning, as an afternoon pick-me-up, or as a brain-boosting nootropic, you likely know how it affects you.

It’s one of the most bio-individual drinks.

And these benefits span further than just the caffeine buzz.

Drinking black coffee specifically can boost your health in many ways.

Cardiovascular Health

Caffeine contains antioxidant ingredients in nature, such as chlorogenic acid and caffeic acid.

Chlorogenic acid protects the cells and tissues from free radical damage, reducing inflammation.

Consequently, this improves blood flow through the blood vessels and reduces blood pressure.

Several types of research show that black coffee intake reduces blood lipid levels, thus reducing the risk of cardiovascular diseases.1James H O’Keefe , James J DiNicolantonio , Carl J Lavie, Coffee for Cardioprotection and Longevity Prog Cardiovasc Dis. 2018

Diabetes Mellitus

Coffee intake has an inverse correlation with the risk of developing type II diabetes.

Many functional components of coffee, such as chlorogenic acid and quinides protect against diabetes mellitus by:

  • improving glucose metabolism
  • increasing the responsiveness of insulin secretion, thus maintaining insulin levels
  • increasing insulin sensitivity and regulating blood sugar levels
  • reduces glucose uptake

Chemopreventive Potential of Coffee

Being an antioxidant-rich food, coffee plays a significant role in protecting against several cancers.

Much research highlights the association between regular coffee consumption and lower cancer risk.

The types of cancers that have been associated with a lower risk include colorectal, renal, ovarian, pancreas, endometrial, esophagus, pharyngeal, and hepatocellular carcinoma.2Masood Sadiq Butt , M Tauseef Sultan, Coffee and its consumption: benefits and risks Crit Rev Food Sci Nutr. 2011

Alzheimer’s Disease

Numerous studies demonstrate an inverse relationship between coffee consumption and dementia and cognitive decline, meaning that the more coffee one consumes, the less likely they are to develop dementia or mental decline.

Research suggests that higher coffee intake over decades also reduces the risk of Alzheimer’s disease.

The proposed mechanism, simply put, states that coffee prevents the formation and accumulation of harmful proteins in the brain.

Moreover, trigonelline, a component of coffee, regenerates the nerves in the brain, thus improving memory.3Masood Sadiq Butt , M Tauseef Sultan, Coffee and its consumption: benefits and risks Crit Rev Food Sci Nutr. 2011

Coffee Protects The Liver

Chlorogenic acid in coffee is hepatoprotective as it prevents liver fibrosis (stiffening).

Research reveals that individuals with preexisting liver diseases who drink coffee have a lower incidence of permanent liver damage (such as fibrosis and cirrhosis) and liver cancer.4Karen Nieber, The Impact of Coffee on Health Planta Med. 2017

Coffee and Weight Loss

Components of black coffee, such as chlorogenic acid and manooligosaccharides have several metabolic effects that explain the weight loss phenomenon seen in those who drink black coffee.

Research also shows that intake of black coffee suppresses appetite and increases daily energy expenditure.

As a result, drinking coffee not only helps you lose weight but also maintains weight loss.5D Icken, S Feller , S Engeli , A Mayr , A Müller, A Hilbert , M de Zwaan, Caffeine intake is related to successful weight loss maintenance Eur J Clin Nutr. 20166James A Greenberg , Carol N Boozer, Allan Geliebter, Coffee, diabetes, and weight control Am J Clin Nutr. 2006

Additionally, a cup of coffee on an empty stomach will also curb cravings.

Coffee and Longevity

Multiple studies demonstrate an association between coffee consumption and decreased infections, cancers, stroke, and cardiac and metabolic diseases.

Research also shows that dose-dependent coffee consumption is inversely associated with total and cause-specific mortality. This means that increasing coffee intake is associated with a lower risk of death.


Autophagy is an anti-aging cellular property of cells.

This phenomenon removes damaged cells or the dysfunctional component of a cell, replacing it with a healthier functional component.

Through direct and indirect mechanisms, coffee induces autophagy.

As a result, it promotes the generation of healthier, functional tissues while clearing the body of the cells and tissues that do not serve a purpose.7Federico Pietrocola , Shoaib Ahmad Malik , Guillermo Mariño , Erika Vacchelli , Laura Senovilla , Kariman Chaba, Mireia Niso-Santano, Maria Chiara Maiuri , Frank Madeo, Guido Kroemer , Coffee induces autophagy in vivo Cell Cycle. 20148Hubert Kolb, Kerstin Kempf , Stephan Martin, Health Effects of Coffee: Mechanism Unraveled? Nutrients. 2020

Intermittent Fasting And Its Health Benefits

Intermittent fasting is the easiest, most accessible way to gain the benefits of fasting without the pressure and stress that comes with more extended fasting.

Such benefits include:

  • Autophagy: the body starts cleaning up by eliminating unnecessary or damaged components of cells and tissues.
  • Ketosis: to produce energy and keep up with the daily physical activity, the body starts to burn the stored fat.

The basic principle of intermittent fasting is simply taking specific, periodic breaks from eating and drinking beverages that contain calories and sugar.

This can be done daily by incorporating a short “feeding window” where you allow yourself to consume food every day or on a longer-fast schedule that includes multi-day fasting with freedom to eat whenever you’d like on the non-fasting days.

Types of Intermittent Fasting

There are many different variations of intermittent fasting, making it easier to choose whichever is suitable for you.9Mary-Catherine Stockman, Dylan Thomas , Jacquelyn Burke , Caroline M Apovian , Intermittent Fasting: Is the Wait Worth the Weight? Curr Obes Rep. 201810Ruth E. Patterson, al., INTERMITTENT FASTING AND HUMAN METABOLIC HEALTH J Acad Nutr Diet. 2016

  • Periodic Prolonged Fasting/Intermittent Caloric Restriction: this form of intermittent fasting consists of fasting for 24 hours or twice a week, followed by eating as much as one desires (ad libitum) for the remaining days of the week.
  • Time-Restricted Fasting (TRF): consists of restricting eating to a specific “feeding window” while the rest of the day is fasted. While the standard seems to be a 16/8 split, benefits can be seen in as little as 12 hours.
  • Alternate Day Fasting (ADF): consists of ‘fasting’ days, in which calorie-free foods and drinks are consumed, alternating with normal or ad libitum days, in which one eats as much as they like.

Health benefits of Intermittent Fasting

Weight Loss

Due to IF’s inherent promotion of calorie restriction, weight loss is inevitable.

A clean intermittent fast helps reduces hunger pangs, thus decreasing appetite over time and stabilizing metabolism.

Studies show that a 16-hour fasting window is most effective in inducing changes in weight.

Yet, a combination of regular exercising and intermittent fasting produces much more effective results in reducing the BMI and waistline.11Stephanie Welton, Robert Minty, Teresa O’Driscoll , Hannah Willms, Denise Poirier , Sharen Madden, Len Kelly, Intermittent fasting and weight loss: Systematic review Can Fam Physician. 2020

Improves Blood Sugar Control in Type II Diabetes

Blood glucose regulation is where intermittent fasting truly shines.

Those with metabolic disorders like type II diabetes can benefit greatly from this type of protocol.

A case series demonstrated that three type II diabetic patients could discontinue their insulin and other diabetic medications when they started intermittent fasting for a minimum of 7 months and a maximum of 11 months.12Suleiman Furmli , Rami Elmasry, Megan Ramos , Jason Fung, Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin BMJ Case Rep. 2018

The side effects of diabetic medications can be bothersome. For this reason, more natural means of blood sugar control like intermittent fasting is more advantageous.

By improving insulin levels are also improved for those with IF.

Following an intermittent fasting regimen, not only increases insulin sensitivity but also lowers insulin resistance.13Suleiman Furmli , Rami Elmasry , Megan Ramos , Jason Fung, Therapeutic use of intermittent fasting for people with type 2 diabetes as an alternative to insulin BMJ Case Rep. 201814Charlene Lichtash, Jason Fung, Katherine Connor Ostoich, and Megan Ramos, Therapeutic use of intermittent fasting and ketogenic diet as an alternative treatment for type 2 diabetes in a normal weight woman: a 14-month case study BMJ Case Rep. 2020

Cardioprotective Effects

Intermittent fasting improves metabolic health by decreasing blood pressure and dysregulated lipid levels.15Kelsey Gabel , Sofia Cienfuegos, Faiza Kalam , Mark Ezpeleta , Krista A Varady, Time-Restricted Eating to Improve Cardiovascular Health Curr Atheroscler Rep. 202116Shengjie Zhu , Prasanth Surampudi, Baback Rosharavan, Maria Chondronikola, Intermittent fasting as a nutrition approach against obesity and metabolic disease Curr Opin Clin Nutr Metab Care. 2020

This tends to go hand in hand with metabolic health, and those benefits will subsequently improve your heart health.

Not to mention a high-calorie diet that includes long feeding windows results in weight gain, high blood pressure and increased blood lipid levels.

Elevated blood lipids such as cholesterol, triglycerides, and LDL are increase the risk of heart diseases.

Impact on Aging

One of the primary causes of aging is the collection of reactive oxygen species (ROS) within the cells and tissues of the body.

ROS are unstable by-products of many cellular reactions that cause oxidative stress. Typically, our bodies contain antioxidants, substances that counteract the actions of ROS.

However, insufficient antioxidants can lead to excess accumulation of ROS. This damagesDNA and proteins, contributing to cell death and progressive aging.17Agnieszka Piotrowska, Ewa Bartnik, The role of reactive oxygen species and mitochondria in aging Postepy Biochem. 2014

A growing body of evidence suggests that intermittent fasting increases the expression of genes involved in protection against oxidative stress.18Martin P Wegman , Michael H Guo, Douglas M Bennion, Meena N Shankar, Stephen M Chrzanowski, Leslie A Goldberg, Jinze Xu, Tiffany A Williams, Xiaomin Lu, Stephen I Hsu, Stephen D Anton, Christiaan Leeuwenburgh, Mark L Brantly, Practicality of intermittent fasting in humans and its effect on oxidative stress and genes related to aging and metabolism Rejuvenation Res. 201519Slaven Stekovic, et al., Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans Cell Metab. 2019

In this manner, intermittent fasting can potentially delay aging.

Improves cognition and brain health

Through indirect and direct pathways, intermittent fasting affects the brain to improve cognitive functioning or prevent or slow the progression of brain disorders.

When the body is in fasting mode, instead of relying on sugar production, the body turns to stored lipids. When lipids are metabolized, ketone production occurs.

In the brain, ketones regulate many processes such as recycling damaged proteins and molecules, tissue repair, and enhancing stress resistance, thus supporting brain health and preventing mental decline.

Research suggests that intermittent fasting also supports neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s, and Multiple Sclerosis.20Jip Gudden , Alejandro Arias Vasquez , Mirjam Bloemendaal, The Effects of Intermittent Fasting on Brain and Cognitive Function Nutrients. 202121Mark P Mattson , Keelin Moehl , Nathaniel Ghena , Maggie Schmaedick , Aiwu Cheng, Intermittent metabolic switching, neuroplasticity and brain health Nat Rev Neurosci. 2018

Psychological Impact

Intermittent fasting has many psychological benefits, including enhanced mood, sense of achievement, pride, and confidence.

This is due to the sheer amount of discipline and self-emotional control required to complete a fast.22Yiren Wang , Ruilin Wu, The Effect of Fasting on Human Metabolism and Psychological Health Dis Markers. 2022 23Ellen Watkins , Lucy Serpell, The Psychological Effects of Short-Term Fasting in Healthy Women Front Nutr. 2016

Prolonged fasting also increases the release of serotonin and endorphins, consequently inducing mood enhancement.24Ellen Watkins , Lucy Serpell, The Psychological Effects of Short-Term Fasting in Healthy Women Front Nutr. 2016

Research suggests that intermittent fasting lowers anxiety and depression levels without increasing fatigue.25Elisa Berthelot, Damien Etchecopar-Etchart , Dimitri Thellier , Christophe Lancon, Laurent Boyer, Guillaume Fond, Fasting Interventions for Stress, Anxiety and Depressive Symptoms: A Systematic Review and Meta-Analysis Nutrients. 2021

It’s important to note that some studies report that short-term, intermittent fasting also increases negative emotions such as irritability, anger, fatigue, and anxiety.

Can you Drink Coffee While Fasting?

Now that we know what intermittent fasting entails, the question arises whether one can drink coffee while intermittent fasting?

Fast-appropriate beverages are often the biggest source of confusion for most intermittent fasters.

When it comes to nonwater drinks, many often want to know, “will (x) break my fast?”

As long as the beverage you are consuming is zero calories, it can be included in the fasting phase.26Mary-Catherine Stockman , Dylan Thomas , Jacquelyn Burke , Caroline M Apovian, Intermittent Fasting: Is the Wait Worth the Weight? Curr Obes Rep. 2018

This certainly applies to drinking coffee, so long as it’s not a fu-fu cup of coffee loaded sugar, milk, and whipped cream from some trendy coffee shop.

At the end of the day its the macros and caloric content in caffeinated beverages that make the difference and not so much the caffeine intake itself.

Herbal teas can also be consumed during your fast.

Black Coffee And Intermittent Fasting

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In my opinion black coffee is the gold standard of acceptable drinks while fasting.

A simple black cup of coffee without any sugar is perfectly fine. If you need it, even a few cups seem to maintain an effective fasting window.

However, if your black coffee contains even small quantities of regular sugar, then this will break your fast.

There are conflicting opinions about adding artificial sweeteners in coffee.

If you want to add a hint of sweetness to your coffee, go for zero calorie artificial sweeteners such as stevia, monk fruit, or erythritol.

Does Milk In Coffee Break A Fast

The goal of intermittent fasting is to drastically decrease your caloric intake. As a result, the body will rely on stored fats to produce energy.

Adding milk to your cup of coffee will break your fast, as one ounce of milk contains over one gram of carbohydrates. Instead of utilizing stored glycogen, the body will utilize the lactose sugar from milk in the coffee to produce energy.

Will Half and Half in Coffee Break My Fast?

Half and Half also break the fast.

It contains a high amount of protein, carbs and sugar that will increase glucose and insulin levels in the body.

It may also contain additives and flavors that will indirectly increase your energy intake in a fasted state, thereby effectively breaking the fast.

What Breaks Intermittent Fasting

In addition to black coffee with milk and a half and half, other types of drinks that break intermittent fasting are:

  • Any coffee containing regular milk, skim milk, half and half, cream, sweetened almond milk, or oat milk. Instead, opt for unsweetened almond milk or play it safe with a simple cup of black coffee.
  • Green juices: Although they may be healthy, they still contain enough sugar, calories, and carbohydrates to break the fast.
  • Energy drinks are definitely a big no; this is because these drinks contain high-calorie additives and moderate amounts of sugar that will break your fast.
  • Caffeine intake in the form of diet soft drinks also breaks your fast.

Does bulletproof coffee break a fast?

Bulletproof coffee, the landmark concept drink from the wellness brand Bulletproof that revolutionized the idea of keto coffee, is touted as an acceptable beverage to add to a fast.

This high-calorie drink is popular for those on a ketogenic diet and is promoted by high-profile keto enthusiasts such as Bulletproof’s founder Dave Asprey.

A typical Bulletproof coffee typically includes some form of high-quality saturated fat such as unsalted grass-fed butter, mct oil, or coconut oil.

But does bulletproof coffee break a fast?

The answer is rather complicated.

Strictly speaking, the calories from a bulletproof coffee should in theory break a fast.

However, considering the drink is mostly saturated fat and assuming you’ve added no sweetener, it would not affect insulin levels in your body.

Nor are the calories significant enough to disrupt autophagy.

If anything, the added fats in the coffee drink will boost ketosis and insulin sensitivity and contribute to appetite suppression which is especially useful in the morning.

Bulletproof coffee lovers especially love the double whammy of physical caffeine energy and ketone brain fuel.

Drinking coffee induces autophagy, whereas bulletproof coffee supports ketosis.

Since we know that fasting has the same benefits, why not drink bulletproof coffee to boost these processes?

Consuming coffee while intermittent fasting will also increase satiety and reduce appetite, thus resulting in gut rest.

So if you are going to drink coffee while fasting, why not add a spoonful of MCT oil or butter and make it bulletproof?


From the research laid out in this article, drinking coffee does not break a fast.

This may come as a breath of fresh air for those coffee lovers who feel bored with just water during those fasting windows.

The truth is that moderate amounts of coffee, so long as its low calorie black coffee, is fine.

The most important thing is that you are constantly monitoring your fasting progress. Coffee has many health benefits, but if it results in inflammatory bowel disease or poor sleep, it’s wise to scale back to just water.


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