Coffee During Intermittent Fasting: To Drink or Not to Drink?

You may have wondered if you can drink coffee during fasting periods. There are both benefits and risks to having a cup of joe during your fast.

Learn what doctors and the latest scientific discoveries are saying about drinking coffee while on a fasting protocol, what the pros and cons are, and how and when drinking coffee can disrupt your fast. 

Intermittent Fasting and Coffee: An Overview

Those who drink coffee find great comfort in their morning brew, and the benefits of this more likely than not outweigh the minimal caloric intake within the fasting window. Doctors and nutritionists agree there’s little danger to drinking coffee while fasting, as long as you keep your consumption mindful.

Coffee Doesn’t Disrupt Your Fast

coffee during intermittent fasting

Coffee, whether black or with a tiny splash of regular or unsweetened nut milk will not disrupt your fast. As long as you avoid sweeteners or other high-calorie additives, the small pleasure of a cup of coffee can actually increase compliance with your fasting program.


Why won’t coffee disrupt your fast? A cup of coffee contains 3-5 calories and minimal amounts of fat, protein, and minerals. That’s simply not enough to cause your body to leave the fasting state.  


A cup of coffee contains 80-100mg of caffeine. Studies show that consuming less than 400 mg of caffeine a day, roughly the equivalent of 4 cups of coffee, is completely safe for most people.

Caffeine per se does not negatively impact your fast, and in fact, many people new to fasting may find caffeinated coffee prevents the drowsiness that can occur during sustained periods without food. 

Creamers and Sweeteners

While black coffee is harmless to your intermittent fasting protocol, you begin to walk a fine line when adding sweeteners and creamers. The proteins in milk, and of course any sugars, stimulate a spike in insulin, which will trigger a break in your fast. 

Doctors recommend avoiding artificial sweeteners, in most part, for health reasons unrelated to fasting. Although in some cases, even artificial sweeteners affect metabolism and lead to a break in the fast. 

Compliance and Control

When reaching for a cup of coffee, or any food or drink for that matter, mindfulness is key. If you cannot drink your coffee black, for example, do you really want the coffee? Or is drinking coffee during fasting periods an attempt to curb your hunger or an excuse to grab something sweet? 

While many find that a cup of coffee helps them stick with their fasting regimen, others may find that coffee triggers greater cravings. Pay close attention to what drinking coffee triggers in you. 

Coffee and Intermittent Fasting: Shared Benefits

Coffee lovers will be glad to hear that the benefits of drinking coffee go beyond the satisfaction of holding a warm cup in hand on your morning commute. Intermittent fasting and drinking coffee have several benefits in common, a few of which are explored below. 

Weight Loss

Weight loss continues to be among the top reasons why most people fast. Not only will your fasting regimen help balance energy spent with energy taken in, but your caffeinated coffee will too. Recent studies reveal that caffeine increases energy expenditure and decreases energy intake, thus resulting in improved body weight management.


The energetic boost caffeine provides is due in part to the presence of ketones. Caffeine produces ketones in the brain, which are used as a source of energy when glucose is unavailable. Fasting is yet another mechanism through which the body reaches ketosis. Rest assured when it comes to promoting ketosis, your morning cup of joe and your fasting protocol are on the same page. 

Brain Health

The presence of ketones is especially important as you age since glucose uptake in the brain decreases over time. Caffeine, like intermittent fasting, reduces the risk of mental declines such as  Parkinson’s and Alzheimer’s diseases and even improves daily brain functions such as mood, sense of well-being, alertness and concentration. 

Insulin Sensitivity

Both intermittent fasting and caffeine are known to improve glucose intolerance and insulin sensitivity in the long run. Scientists are still studying the underlying mechanisms that explain this effect, but regular coffee consumption appears to reduce the risk of type 2 diabetes by up to 42%

In the short term, caffeine has the opposite effect. Insulin sensitivity is reduced, and glucose intolerance rises while you are drinking your cup. For this reason, it may actually be best to drink your coffee without food. 


Both intermittent fasting and coffee reduce chronic, systemic inflammation, and many related diseases. 

Scientists have found that drinking coffee reduces inflammation, while caffeine supplements alone do not. You always knew there was something special about your cup of coffee, and you were right! 


Autophagy is a naturally occurring process in the body through which damaged cells are cleaned out to make way for new cell production. An increase in autophagy is one of the main reasons many people fast. 

Coffee too, promotes autophagy. A recent study observed an increase in autophagy throughout the heart, muscles, and liver.


Some coffee drinkers claim the drink’s appetite-suppressing effects help them comply with their intermittent fasting protocol. While this may be true for some, it’s not true for everyone. Science has yet to associate coffee with appetite suppression. 

Whether or not coffee works this way for you could be related to your genes, how you metabolize caffeine, and your aversion to bitter tastes.

Coffee While Intermittent Fasting: The Risks

There are very few risks  of drinking coffee while doing intermittent fasting, and these risks are generally related to a high caffeine intake. 

coffee and intermittent fasting

Sleep Disturbance

Intermittent fasting improves the quality of your sleep, yet too much coffee can interfere with this. Doctors suggest limiting your coffee consumption to 4 cups per day. If you’re sensitive to caffeine, avoid drinking coffee in the afternoon and evening.

Getting too little sleep not only makes you miserable, but will reduce the impact of your intermittent fasting regimen, and may result in weight gain. 

Caffeine on an Empty Stomach

Drinking coffee on an empty stomach can exacerbate issues for those who have inflammatory bowel disease, irritable bowel syndrome or gastroesophageal reflux disease. If you’re dealing with any of these issues, you may want to be careful with your intake, or try a cold brew, which is generally less acidic. 

Switch to Decaf

Some of the aforementioned mentioned benefits, such as an increase in insulin sensitivity, and an uptick in autophagy stand true for both decaf and regular brews. If it’s coffee you love, but the caffeine isn’t working, you’re not missing out by switching to decaf.

If You Must Drink Coffee During a Fast

If you simply can’t live without your cup of joe, you don’t have to. Just keep in mind the following so as not to disrupt your fast by drinking coffee:

Coffee Creamer Do’s and Don’ts

Black coffee during intermittent fasting is best. If that’s not an option, a tiny splash of cream is likely OK and it won’t change how much fat you’re burning. It might, however, slow the rate of autophagy. 

Pure fat is a better option than cream, and will have a small effect on blood glucose or insulin sensitivity. Bulletproof coffee and intermittent fasting are thus the perfect pair. Grass-fed butter and coconut oil add flavor and creaminess without causing metabolic changes that would disrupt fast.

When ordering in a coffee shop, beware that the “cream” used is often a mix of milk and cream and not full fat. Protein and carbohydrates in milk can cause you to break your fast. 

Coffee Sweetener Do’s and Don’ts

If you must have a little sweetness in your coffee, choose wisely. Sweeteners will break your fast by triggering insulin secretion. Artificial sweeteners such as Stevia, Swerve, Aspartame and Splenda will not break your fast, as they appear to have no effect on insulin secretion or blood glucose. You may wish to avoid them, however, for other health reasons. 

Cinnamon won’t break your fast, and can also increase insulin sensitivity. Unsweetened cocoa powder (just a little) and ginger may also safely be added as flavor for your brew. 

At your local coffee shop, beware of hidden sweeteners. Soy, rice, and nut milk alternatives are usually sweetened. 

Coffee and Intermittent Fasting: The Verdict 

If you enjoy your cup of coffee, if it makes you feel good and it helps you maintain your fast, by all means, enjoy it! Be mindful of creamers, sweeteners and other additives, and don’t overdo it. Drinking coffee while fasting is a personal choice for everyone, and for some, it may be better to completely abstain. 


Thanks for your question! Putting it shortly, consuming anything with calories will break your fast; the only exceptions are water, tea, and coffee. Speaking about bullet-proof coffee, the opinions of different fasting specialists vary, but it’s still a high-calorie drink, so it will technically break your fast. On the other hand, bullet-proof coffee is high in fat and low in carbs, so it will have a small effect on your blood sugar, if this is your fasting goal.