What Can I Drink While On Intermittent Fasting And Keto?

minute read | Last update: Dec 1st2022

This article is backed by studies and reviewed by a certified dietician.

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"What can I drink while on intermittent fasting and keto" was the first question I asked myself the first time I paired my keto diet with an intermittent fast. My primary concern was the unnerving thirst I felt during my fasting windows. I knew I could not afford to drink just anything, as I had to keep my carbs and sugars down as much as possible.

The ideal drink that can be consumed when pairing intermittent fasting and keto should be free of calories, low in carbs, or not substantially affect your caloric deficit required for weight loss. Suitable options include water, green tea, black coffee, and diluted apple cider vinegar.

Having seen this, I knew exactly what to avoid and what not to avoid in the context of calories. I also knew drinks filled with sugar and even artificial sweeteners were off the list. Now I knew exactly what to drink without worrying about spikes in blood sugar level or excessive carbs intake.

Keep reading to find out what makes a drink suitable for consumption during a fast, what drinks to take and which to avoid, plus which supplements can be taken without any detrimental effect on your weight loss goal.

Why is it important to stay hydrated during intermittent fasting and keto?

Combining a ketogenic diet with an intermittent fast means, you will have your keto meals within an eating window. During the period outside your eating window, you would be observing a fast without any solid meals until it's time to feed.

Staying hydrated during the fasting window is crucial because you cannot eat solid foods high in calories until your eating window. This is so that you do not interfere with ketosis and consume calories that could contribute to you exceeding your daily macro limits.

However, the liquids taken must be low in calories or contain absolutely no calories. Water, plain coffee, and unsweetened tea are some of the choices you have for drinks when on a fast.

What are the different categories of fasting based on what I can drink?

Strict fasting

During a strict fast, the only liquid consumed is water without any additives like electrolytes or fruit slices. Until it is time for your eating window, water is all you are allowed to drink.

Open fasting

Maintaining a caloric deficit and only eating during eating windows are the most critical factors when on a fast and a keto diet. If taking a drink like unsweetened plain coffee with a tiny amount of cream can help you persist for more extended periods during your fast, then go ahead.

Most times, the fluids consumed in an open fast for extended periods of fasting are often taken at the start of the day. The allowed amount of calories during this period of fasting with a ketogenic diet is 20kcal.

Should you decide to proceed with an open fast, fats are better and healthier, as fats do not raise blood levels. On the other hand, carbs can interfere with fat-burning and raise blood sugar levels over time.

Open fasting is great if you are just getting started, and you need to build up a tolerance to the hunger associated with intermittent fasting.

Moderate fasting

Moderate fasting allows for beverages that are free of calories apart from water. Drinks like black tea and unsweetened plain coffee could help in improved metabolism and heart function.

Non-calorie-containing drinks do not break your fast, neither do they increase your blood sugar levels. It is also crucial to mention that autophagy (disposal of dead cells and cell creation) still occurs on a moderate fast.

What should I look out for in my choice of beverage when during intermittent fasting and keto?

When selecting what drink to consume during your fasting window, you mustn't take any drink that could make you "break" your fast. Breaking your fast in this sense means consuming any macronutrient, be it protein, fat, or carbohydrates.

There are two vital factors to consider when quenching your thirst on an intermittent fast paired with a ketogenic diet.

The drink must either contain zero calories or be low in calories.

Since intermittent fasting emphasizes calorie deprivation and timed eating windows, the drinks you consume during the fasting window should not be loaded with calories.

Zero or low-calorie calorie drinks that can be consumed include water, mineral water, and black coffee. Just be sure not to add any sweeteners to the coffee, especially white sugar and syrups. There is also a study showing that black coffee could support ketone production.

Apple cider vinegar is also a great choice, as it helps decrease blood sugar levels and support digestion. Stevia works just fine if you crave something sweet. However, Stevia could trigger hunger in some individuals, so you want to be cautious.

Bone broth can be taken, but this is mainly if the fast is a twenty-four-hour fast.

The drink must be free of artificial sweeteners and sugars.

Sugar contains calories, and table sugar has been shown to increase blood sugar levels, thanks to its glycemic index rating. Drinks containing sugars and high in calories like smoothies, fruit juices, and sodas are off the menu.

What drinks are okay to consume during your fasting window in IF and keto, and why?

The following liquids can be taken when pairing intermittent fasting with a ketogenic diet;


Water is free of calories and contains no carbs, plus it is almost available everywhere.

Mineral water

Mineral water is still regular water, but with salts and minerals like sodium sulfate and calcium carbonate. Mineral water has also been shown to keep the heart healthy by increasing the levels of good cholesterol and reducing bad cholesterol levels.

Plain coffee

Plain coffee without additives is a great option while intermittent fast, paired with a keto diet—no additives like syrups, table sugars, or honey.

Unsweetened tea

Unsweetened tea has two significant advantages over sweetened tea when it comes to intermittent fasting and keto. Unsweetened tea is lower in calories and contains little to no sugar.

Common examples of unsweetened tea suitable for consumption while losing weight include green tea, black tea. Rooibos, peppermint, and camomille.

Apple Cider Vinegar

Apple cider vinegar should be diluted in water to soften the harsh taste when undiluted. Diluted apple cider vinegar contains no carbohydrates, dietary fibers, or protein.

The dilution ratio for apple cider vinegar with water is one to two tablespoons of ACV in one eight-ounce glass of water. Apple cider vinegar offers many health benefits like aiding weight loss, reducing blood sugar levels, and feeling fullness when taken before a meal.

What drinks can I use to break my fast during my eating window while on IF and keto?

Below are the drinks which you can use to break your intermittent fast;

Fruit-infused water

Fruit-infused water is excellent for breaking a fast. When adding fruits, avoid those high in sugar like watermelon, cherries, and grapes. Grapes contain about 16 grams of sugar, while cherries have 8 grams of sugar per 100 grams.

Go for healthier alternatives like lime and cucumber that have low sugar content. Both cucumber and lime contain 1.7g contain 100 grams of sugar per 100 grams. You don't have to worry much about your blood sugar level spiking with such low sugar content.

Non-dairy milk

Regular milk from cows contains as high as 122 calories,12 grams of sugar, and 12 grams of carbs per eight ounces. However, there are other choices, such as significantly lower calories and sugar than dairy milk.

Almond milk (unsweetened) contains zero sugar, 30 calories with 1 gram of carbohydrate in a 240ml cup. When buying almond milk, avoid buying sweetened almond milk or anyone fortified with protein. The sugar content is usually higher in other variants like chocolate-flavored almond milk and vanilla-flavored almond milk.

Keto-friendly beer/alcohol

Keto-friendly beers with zero carbohydrates can be taken to break an intermittent fast. Zero-calorie drinks like tequila and vodka should be taken in moderation. This is because alcohol has been shown to trigger hunger and increase one's appetite.

Healthy fats (Medium Chain Triglycerides Oils)

Four capsules of MCT oils can be mixed with a low-calorie beverage such as unsweetened coffee. MCT oils also provide several benefits during intermittent fasting, like increased weight loss and improved brain function.

What drinks should I avoid entirely while on keto and intermittent fasting?

Drinks to avoid when combining a weight loss routine such as keto with intermittent fasting include;

Diet soda

Though diet sodas are free of table sugar, unlike their carbonated and fizzy counterparts, they contain artificial sweeteners. Common sweeteners used include Saccharin, Aspartame, and Acesulfame K.

Be mindful of terms like "sugar-free" and "low-calorie," and steer clear drinks with them during both your fasting and eating window.

Lemon juice

Never drink lemon juice in the event of intermittent fasting or a keto diet. Lemon contains 9g of carbohydrates and 2.5g of sugar. If you ever consider lemon juice, dilute one slice of lemon in an eight-ounce glass of water.

Sweetened coconut water

Sweetened coconut water contains 91 calories and 22.5 grams of sugar in a 240ml cup. The sugar content of sweetened coconut water is slightly short of half of the daily carb limit of 50g during keto.

Fruit juice

Fruit juice has the fiber removed, so the effects on your blood sugar will hit as hard as a soda. A 240ml serving size of fruit juice contains around 110 calories and anywhere between 20-25 grams of sugar.

What supplements can I take during my fasting window that wouldn’t be detrimental to my fast and keto diet?

You could take supplements during either your fasting window or preferably save them till your eating window. These include;

Drinks rich in electrolytes

Some people tend to sweat highly in the event of a fast, which means a loss of electrolytes and a drop in body fluid. Electrolytes like sodium and potassium are lost and will need to be replaced.

Sports drinks and electrolyte-infused water can be taken if you start feeling dizzy and thirsty.

Collagen powder

The best supplement to have while on a keto diet, collagen powder, can be taken during your fasting window. Collagen powder provides mainly protein and aids weight loss which is what you're aiming at.

I recommend Authentic Keto Collagen Powder for your fasting window. Be sure to stay within the recommended daily intake of 2.5 to 15 grams.

Final Thoughts

It requires a lot of discipline to indulge yourself with drinks rich in sugars that tend to keep us full for more extended periods, such as fizzy drinks. Knowing what can be drunk during eating windows while focusing on the long-term journey ahead is essential.

If you are just new to keto and looking to pair it with intermittent fasting, you might want to consider an open fast. People who have been involved in keto and IF for a more extended period may be used to strict fasting. Pick what works for you, and remember, avoid artificial sweeteners at all costs.


Why should I pair intermittent fasting with a keto diet?

Taking meals during an eating window, as against three times a day, aids in weight loss, increases your metabolism rate and can trigger autophagy in your system.

Can I consume bone broth to break my fast?

Yes, you can, especially if you are going with the moderate fast that allows liquids with calories up to 20 kcal.

Which type of almond milk do I go for when breaking my fast (sweetened or unsweetened)?

Unsweetened almond milk is undoubtedly the best option. Fortified or sweetened almond milk, e.g., chocolate almond milk, has more carbs and sugar than you require.

How much coffee can I take per day if I decide to go with plain coffee during my fasting window?

Experts warn against exceeding more than four cups per day. 2 to 3 at most should be fine.

Is there any exception where I can have some form of solid food instead of just liquid during my fasting window?

The Warrior Diet is an intermittent fasting plan that allows you to have small amounts of fruits, vegetables, and hard-boiled eggs still with water or coffee.

What recommendations can you make for low-carb keto friendly beers to break my fast?

You can check out Bright Tangerine Sparkling Ale with 2 grams of carbs. Corona Premier is also another excellent choice, with 2.6 grams of carbs.

For diabetics who are fasting, what drink(s) can you take during your fast, and which should you avoid?

Apple cider vinegar, and sports drinks rich in electrolytes are great options for diabetics on a keto diet and IF. Regular soda and fruit juices are totally off-limits.

About the author

The Authentic Keto Team is here to bring you health tips that help you with losing weight fast. We focus on a clean keto diet for beginners because we believe that is the easiest and most simple way to healthy eating. Our keto weight loss tips will not only bring you into ketosis fast but will also help you to improve your mental health, sleep problems, and wellness.

- Our goal is to make keto success easy. -

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