Will Cold Brew Coffee Break a Fast? Is It KETO Friendly?

Cold brew coffee is a refreshing drink any time of day. But can you safely drink it while you’re fasting or following a KETO diet? Here’s what you want to know.

Cold brew coffee without any additions is KETO friendly and will not break a fast.  Many cold brews have other things added in for a different taste. Most cold brew add-ins like dairy, syrups, and fruit will make your drink break your fast. Some add-ins are still KETO friendly but most are not.

Let’s get into the details a little bit more. While the answer might seem straightforward, it can get a little complicated.

Cold Brew Coffee Nutritional Values

To know if something breaks a fast and/or is KETO friendly we need to know what’s in it. What kind of nutrients are in there?

Basic cold brew is very simple. You put coffee grounds in a container. Then you add water and wait. This means it’s very similar to any other type of coffee. It’s just extracted with cold water instead of hot. That gives a different taste profile but doesn’t change the nutritional value compared to hot brewed coffee.

Because cold water is used, cold brew tends to extract less quickly. That’s why the brew time is much longer. When brewing coffee, you extract a part of the solids in coffee beans and dissolve it into the water (usually about 20% of the weight of the beans.) So there are a few calories in a cup of cold brew, just like normal coffee. It depends on the type of beans you’re using and how much exactly. That soluble material has some calories and carbs in it but it’s very minimal.

The carbohydrate and calorie content in cold brew coffee is minimal. On average you’ll find less than 0.1 grams of carbohydrates in 100 ml of coffee and maybe 1 calorie in a cup. So unless you’re drinking multiple liters a day, it’s not of any consequence on a KETO diet or a concern for fasting.

If your specific cold brew drink is KETO friendly does depend on what else is in it.

Black cold brew without any additives is KETO-friendly.

Is Cold Brew Coffee KETO Friendly?

Normal cold brew is often served with ice. That means you’re basically drinking black coffee with ice. Sure the extraction is different with cold brew which means the taste is different but there is no considerable difference in nutrition compared to ‘normal’ coffee.

And it’s pretty well known that black coffee without sugar or milk is certainly KETO-friendly. There are trace amounts of carbs in coffee but you can’t really drink enough coffee in a day to make that a problem. A 12 oz. serving of coffee has less than 1 gram of carbohydrates.

There are even indications that it’s beneficial to consume a little bit of caffeine during KETO.

Of course, everything changes when you start adding things to the cold brew. But completely natural, you have nothing to worry about in a KETO diet.

Does Cold Brew Coffee Break a Fast?

Black cold brew without anything else will not break a fast. At least for intermittent fasting purposes. Pure fasting means you only drink water and some minerals. There is more than minerals and water in coffee. However, the other things are so minimal that it doesn’t really matter that much.

If you’re fasting for medical reasons, follow the instructions of your doctor. Which usually means, no coffee.

Suggested post: Does Vietnamese coffee break a fast?

So now I’ve mentioned that things change when they add in at least twice, let’s take a look at those add-ins and HOW they change the answer.

Cold Brew Add-ins

So, cold brew coffee without anything else doesn’t break a fast and is KETO friendly.

Where things change is when you start adding things. Cold brew is a very popular drink to mix with a ton of other tastes. The smooth taste means it does play well with many other different tastes. There are tons of different things you can mix into cold brew.

There are very different things on that list with very different nutrition profiles. So that’s why we have to look at the specific add-in to see if it breaks a fast and/or is KETO-friendly.

Here are the most popular Cold brew add-ins and what their nutrition is like;

  • Orange
  • Tonic (sometimes with fruit)
  • Milk (different types)
  • Raspberry
  • Vanilla
  • Liquor

I’ll make it easy. Any of these add-ins will break a fast except vanilla. Vanilla is an edge case. If you put some vanilla extract in your cold brew, it’s technically not fasting because there are a few calories and a bit of sugar. However, for intermittent fasting, it’s not a huge deal. So if that’s what gets you through a few more hours of fasting it might be worth the slight calories.

I’ll go deeper into if the things above are KETO-friendly or not.


Probably the most common add-on to cold brew is orange and sometimes other citrus fruits. Even though you probably don’t add a lot of orange juice to your cold brew, it still contains a considerable amount of carbs. All fruits do.

Carbs are the enemy when on a KETO diet. That means it’s quite likely that the little bit of orange or citrus juice is going to kick you out of ketosis.

Tonic (sometimes with fruit)

Normal tonic water is quite high in sugar which means it’s not suitable for KETO and will break your fast.

There are Diet Tonic waters available that would make it suitable for KETO. There will be a different sweetener used so be careful since not all artificial sweeteners are something you want to ingest, KETO or not.

If you’re in a restaurant or coffee shop, it’s worth asking them if they have diet tonic water. Not many places do but you can always ask.

However, if the tonic is mixed with other fruits, it’s pretty much always going to be unsuitable for both fasting and

Milk (different types)

As with all coffee, cold brew gets mixed with milk/dairy products. There are tons of dairy products and replacement products you can put in cold brew.

For KETO, normal fresh milk isn’t the best choice but there are options that are KETO-friendly. Heavy cream, coconut milk, and macadamia milk are some popular choices that work well on a KETO diet.


Raspberry itself is a pretty common thing to mix with cold brew. Raspberries like most other fruits have too many carbohydrates to eat on a KETO diet. And since for cold brew they often actually use jam, there is even quite a bit of added sugar.

This is a definite no-go.


A teaspoon of vanilla extract does have about a gram of carbohydrates but since you won’t be using more than about a teaspoon in a serving of cold brew, that’s not a big issue.

When you start drinking several servings a day it will start adding up. But since cold brew is pretty high in caffeine it’s not likely that you’ll be having five a day.


If there is alcohol in something, it’s not Keto-friendly period. While technically alcohol isn’t the same as carbs, in a KETO context it’s almost as bad. When you drink alcohol, the liver makes it its highest priority to get rid of it from your bloodstream. That means your liver can’t metabolize fats and produce ketones for that time.

And that’s if you drink something that completely lacks any other carbohydrates. Most drinks still have carbs as well.

By the way: To keep your cold brew good for longer, it’s important to store it in an airtight container.


Welcome to CoffeeImproved! Since falling in love with coffee, I've been on a journey to improve my morning cup day by day. That means I've tried many different brew methods, beans and equipment and experimented with all of them to find what I like. This is where I share what I've learned with you.

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