Does Espresso Break A Fast? (Unveiling The Truth!)

There is mounting evidence that intermittent fasting causes significant metabolic change, including changes in insulin sensitivity. It could help you shed excess body fat.[1]

Espresso packs a lot of caffeine into a small package to give you energy. So, might it be a match made in heaven?

If espresso consumption is the joy of your life, you might wonder: Does it work with intermittent fasting, or does espresso break a fast?

Here, I address these questions and discuss how espresso could help you both during and outside of the fasted state.

The answer to Will espresso break my fast? is probably not. However, that depends on how you prepare it.

Black Espresso

Plain black coffee or espresso are fine during a fast; the single-digit number of calories does not have sufficient metabolic effect to break a fast.

However, some people warn that the elevated blood sugar levels associated with coffee could interrupt fasting for those consuming more than their usual coffee intake.

Espresso With Milk/Cream

Whether adding milk is OK depends on your fasting goals.

If you are only having a very small amount and are using keto/low-carb approaches to complement your intermittent fasting, or if you are just eating a low-calorie diet over a certain period, then a little dairy is OK.

Espresso With Sugar

This is the most controversial additive. It is anti-keto, and even a small amount adds enough calories to undermine an intermittent fast.

True, if you use only a cube, it is still in the early double digits calorie-wise. So, small amounts are acceptable if the object is to consume a lower-calorie diet over a fasting window. 

Adding Sugar To Espresso

Flavored Espresso

Flavored espresso beans are uncommon. With espresso, the difference is in how a shot is pulled, what is added, how it is added, etc.

That aside, flavored coffees do not have more calories than regular coffee, so they are OK during a fast (FYI: there is such a thing as espresso-flavored coffee).

However, if you are a stickler about processed-food additives, then flavored coffee might not be for you.

Bulletproof Espresso

For most intermittent fasting (aka IF) diets, even with keto, Bulletproof espresso is not OK to have during the fasting period itself because it has so many calories. Healthy fats are still calorie-dense.

Bulletproof coffee, by definition, contains low-toxicity beans and grass-fed butter, plus an oil rich in MCTs (medium-chain triglycerides), with coconut oil in coffee being a common choice.

As you might imagine, it is not for everybody, and excessive use is not good for anybody.[2]

Protein Coffee/Proffee

As the name suggests, this is protein powder combined with coffee. Both protein powder and amino acids (such as BCAAs) break a fast.

However, neither will cause a blood sugar spike as sugar does, so, this would be a great choice outside the fasting period.

iced protein coffee on a countertop next to a scoop of protein powder

What Can You Add To Espresso That Won’t Break A Fast?

Artificial Sweeteners

Since they have zero calories, they do not break a fast–theoretically, at least.

Growing evidence suggests that most artificial sweeteners defeat their purpose, as they have metabolic effects unfavorable to weight loss and metabolic health.


There is a trend of putting a little salt in coffee or espresso as a pre-workout or weight loss aid; indeed, it adds zero calories.

Moreover, most people find that salt softens the potentially bitter taste of black espresso, reducing the desire to add milk, sugar, or artificial sweeteners.


At first glance, this looks to be the most uncontroversial additive for coffee while fasting; it offers so many health benefits in its own right.

However, large amounts are toxic: it contains the blood thinner coumarin. So, if you consume multiple shots of espresso per day, do not put cinnamon in all of them.

Vanilla Extract

Calorie-wise, this is fine. Note, however, that most people find it tastes awful if you add too much. Plus, some extracts contain alcohol, which gives the body calories in a sugar-like form.


This is always fine, but you might be thinking, is this an additive? Well, espresso and water are the defining ingredients of one of the most popular espresso drinks, the Americano.

Unsweetened Almond Milk

It has fewer calories than other nut milk, so if you stick to a small amount, you are getting very few calories.

However, like any calorie-containing additive, avoid it during strict intermittent fasting.

Almond Breeze Almond Milk In A Small Jug

Unsweetened Coconut Milk

Coconut milk has more calories than other nut milk, with most of the calories coming from fat; therefore, even a small portion could break your fast.

However, it is the same type of fat in bulletproof coffee, a keto favorite–so this is potentially a great option once you are out of the fasting window.

Some Low-Calorie Creamers

Many of these have so few calories that they would not break a fast.

However, bear in mind that creamers are processed food; moreover, they need added ingredients to replace the missing natural sugars and fats.


Like coffee, pure cocoa powder has almost no calories. It is also a great way to get more mood-boosting, energizing, and antioxidant compounds.


Yes, I know it sounds strange, but pure tea adds no calories and gives a different taste–as well as a multitude of healthy compounds.

I tried it once accidentally, and I found that the coffee’s flavor dominates. Perhaps it would be different with a stronger tea.

cup of coffee next to a cup of tea with lemon

How Often Should You Drink Espresso While Fasting?

A consensus across sources is that eating anything over 50 calories will break a fast; however, most sources add that, ideally, you should avoid any calories during a fast.

Another general rule is that you should drink coffee during your fast as often as you would if you were not fasting. Just beware of high-calorie additives.

If you want to use coffee to help you through the fast but you are not a coffee drinker, perhaps try incorporating it into your diet before you start your IF program–this will reduce the chance of both metabolic disruptions to the fasted state and shakiness that could force you to break your fast.

On the other hand, if you are used to coffee or espresso, do not worry: Aside from trying different espresso coffee beans, you also could order (or use your espresso machine to make) different pulls–ristretto or lungo.

For some people, the acidity of coffee could become an issue, especially when consumed on an empty stomach.

On this note, I was surprised to learn that ristretto is the less acidic shot of espresso, despite being more concentrated in flavor.

Moreover, surprisingly, espresso is, on average, less acidic than regular coffee.

The Perfect Timing For Sipping Espresso During Fasting

There is no scientifically-supported perfect time to drink espresso or coffee during a fast. You just have to use common sense and listen to your body; the normal rules apply.

Avoid caffeine within a few hours of bedtime, stay hydrated (since caffeine is drying to the body), and stop consuming caffeine if you feel tightness in the chest, uncomfortable jitteriness, or digestive distress.

Making Espresso Roast

Espresso & Fasting: The Surprising Perks And Potential Pitfalls!

Interestingly, many of the benefits of intermittent fasting are similar to the benefits of drinking coffee.[3]

And, to some degree, this could also be said of the keto diet.[4]

More On Metabolism

A 2017 piece in the Journal of Traditional and Complementary Medicine corroborates the above statements while discussing coffee’s complicated effect on insulin response and glucose metabolism.

It further concludes that short-term coffee/caffeine consumption negatively impacts blood glucose levels, while long-term coffee consumption–whether regular coffee or decaffeinated–has the opposite effect: increased insulin response and decreased risk of type-2 diabetes mellitus.

The researchers propose that metabolic health benefits arise not from caffeine but rather from the many antioxidants and anti-inflammatory compounds in coffee, which improve the body's ability to use energy and regulate blood sugar.

It further confirms that habitual coffee drinkers develop a tolerance to coffee’s usual bump in blood glucose.[5]


Both keto and IF programs cause the body to go into ketosis, an altered metabolic state that involves fat loss, but there might be yet another phenomenon in play:

A 2014 study reports that the compounds in coffee promote autophagy, much in the way fasting does.[6]

While more research is needed to reinforce these claims, autophagy might stimulate fast loss/weight loss, along with causing improvements in brain health, including reduced risk of neurological diseases.

Interestingly, these benefits appear to arise from improved inflammation response, the same basic mechanism by which coffee offers numerous benefits.[7]

Blood Pressure

A 2022 Harvard Health study found that habitual coffee drinkers experience less of a rise in blood pressure after espresso but react more like non-coffee drinkers to an injection of pure caffeine.

Decaf espresso generated a noticeable rise in blood pressure among non-drinkers. Clearly, caffeine is not really the main culprit.

This piece goes on to discuss other suspected benefits from coffee, including improved brain function (i.e., alertness, cognitive function)--but acknowledges that coffee also can have adverse effects: heartburn, withdrawal headaches, etc.[8]

Subjective Experience

Cognitive function and alertness might not just be side benefits: they could help you get through a long fast.

Beware that buying coffee at a cafe might tempt some people to break a fast.

For example, if you walk into a coffee shop and smell the freshly brewed coffee mixed with baked goods, and then watch someone else walk out with a delicious cup of cappuccino–you could feel unbearably deprived.

Alternatively, you might feel the opposite–maybe going to the coffee shop is a part of your routine that you would miss.

Either way, be sensitive to how your daily habits enforce or hinder your fast.

Personally, I find coffee rather meditative, whether caffeinated or not. The smell of it gets me to breathe a little deeper and slower.

This calm and invigorated state has helped me to push through difficulties.

Pulling Espresso Shot On The DeLonghi EC155

Exploring Coffee Delights During Fasting Beyond Espresso

While intermittent fasting, you may have any coffee black (regular and decaffeinated coffee, unflavored or flavored coffee, dark to light roast) and any grind–grind the beans yourself or buy any coffee grounds.

All brewing methods are allowed: French press (and derived devices), siphon, coffee maker drip coffee, filter, or whatever you have got.

You may use any brand of coffee bean you want (but the health-conscious might want to seek out low-toxicity and high-quality coffee beans).

This is not to mention cold-brew or nitro coffee, both of which tend to taste smoother without additives or artificial sweeteners–making them especially suitable for fasting periods.

Across the web, I see that hot coffee is generally higher in antioxidants, but people find cold-brew coffee to be a bit kinder to the digestive system.

Ultimately, you will assess your own energy, taste, health, and digestive experiences when finding your perfect coffee-drinking schedule while fasting.

Related Espresso And Fasting Questions

Can you drink coffee when fasting for blood tests?

While some metabolic tests are not affected by black coffee–coffee and caffeine products, in general, are typically prohibited before a fasting blood test.[9] To be on the safe side, do not drink coffee, even decaf coffee (which still has a little caffeine); stick to pure water. If drinking coffee that day means a lot to you, ask your medical practitioner.

Can you drink coffee when fasting for an ultrasound?

Whether or not you may drink coffee prior to an ultrasound depends on the purpose of the ultrasound. For an abdominal ultrasound, some doctors indicate that you must have a completely empty stomach. However, fasting is not necessary in most cases.[10]

Do flavored coffees break a fast?

No, flavored coffees do not break a fast since they have no more calories than plain coffee. However, flavored coffees have artificial flavoring chemicals.

Can drinking espresso make fasting more effective?

Generally, yes. Regular coffee consumption has many benefits that work sympathetically with intermittent fasting.

Final Thoughts

Whether or not espresso will break your fast depends on how you drink it. The safest option is always black coffee, regardless of the coffee type.

Interestingly, many of the benefits of coffee mirror those of fasting and keto dietary approaches.

However, for those new to drinking coffee, it causes bumps in blood glucose and blood pressure that might disrupt a fast.

Therefore, to increase your chances of success, get comfortable with drinking coffee before beginning an intermittent fasting diet.



Kayla Stavridis

Head of Marketing

Kayla Stavridis
Kayla Stavridis is a coffee enthusiast and Head of Marketing for Barista HQ. She blends her professional insights and experience with a deep passion for all things coffee. Kayla offers a unique, hands-on perspective on coffee culture and trends. You can find her sipping a cold brew with just a touch of milk on the beach in the afternoon and a Corona with lime in the evening.

My favorite drink? I'd go with... Cold Brew

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