Does Coffee Break a Fast?

Written by Stephen Anton PhD on October 21st, 2020

Almost two out of three American adults drink a cup of coffee per day.

With the surging popularity of intermittent fasting, many are wondering:

Can you drink coffee while fasting?

Do additional ingredients break a fast?

Which types of coffee break a fast?

Find the answers to these and other questions related to use of coffee while practicing intermittent fasting below.

Can You Drink Coffee While Fasting?

Technically, any calories “break” a fast.

However, the fasting state can be maintained when very few calories are consumed.

While a zero calorie fast maximizes results, an extremely low calorie fast still provides substantial results.

“So, can I drink coffee while fasting?”

Black coffee, yes.

A cup of black coffee has less than 5 calories and no carbs or protein so it practically has no effect on fasting.

For all other types of coffee, the sections below provide additional information.

Do Additional Ingredients Break a Fast?

People fast for many reasons.

Two of the most popular are:

Fat loss through ketosis

Ketosis improves fat loss (among other things)

Cellular cleansing through autophagy

Autophagy improves overall cell function (improves overall health)

If the goal is to maintain ketosis, some calories can be consumed provided they are mostly from high fat additions, such as cream, butter or medium chain triglycerides.

These additions will not take the body out of a ketogenic state, so they can be added to coffee without breaking ketosis.

If the goal is to enhance autophagy, then very few calories should be consumed during fasting.

Here are a few general guidelines you can follow:

Coffee and Autophagy

If you are focused on autophagy, your coffee should have less than:

25 calories

3 grams of carbs

1 gram of protein

Autophagy is delicate.

The closer to black coffee you can get, the better.

Coffee and Ketosis

If you are focused on ketosis, your coffee should have less than:

100 calories

7 grams of carbs

3 grams of protein

As you can see, ketosis is not as delicate as autophagy.

Still, the closer to zero you can get in all categories the more benefits you will experience.

Which Types of Coffees Break a Fast?

Coffees come in many different styles.

Below is a list of the 22 most popular types of coffee and whether or not they break a fast:

Final Words on Fasting with Coffee

Overall, fasting and coffee can coexist without breaking a fast.

In fact, there may be synergistic effects when fasting and coffee are combined correctly.

To help create a proper pairing, keep these two things in mind:

Black coffee is best

If you have to add ingredients, limit calories, carbs, and protein


Dr. Anton

I’ve had the privilege of studying the fields of obesity, metabolism, and aging for the past 20 years and felt an increasing desire to share what I’ve learned with as many people as possible the past few years.

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