Blog Diets Fasting 7 Liquids To Drink While Fasting that Won’t Bring You Out of Ketosis

7 Liquids To Drink While Fasting that Won’t Bring You Out of Ketosis

Ketosis is a metabolic state where the body, deprived of its usual supply of carbohydrates, begins to burn fat for energy, producing ketones in the process (9).

While in this state, some individuals claim to experience enhanced fat loss, improved mental clarity, and potentially a reduction in risk factors for chronic diseases (9). Many who practice Intermittent Fasting or follow a ketogenic diet aim to remain in ketosis to reap these purported benefits.

However, achieving and maintaining ketosis requires careful management of your diet, even during fasting periods. How “clean” your fast remains is influenced by what you consume during those hours.

Consuming certain liquids can inadvertently provide enough carbohydrates or calories to break your fast or pull you out of ketosis.

Here’s a review of the best options that will keep you hydrated and fasting “clean,” ensuring you stay on the path to achieving your weight and wellness goals.

What Liquids Can I Drink While Fasting?

While on a strict fast, you should only consume zero-calorie beverages. The only true zero-calorie drink is water; anything else will have some level of calories or carbohydrates.

However, fasting on plain water alone can be challenging. Many prefer to drink other liquids during their fasting period for variety.

Fortunately, there are several options available that will not break your fast or take you out of ketosis.

1. Plain Water

Water has zero calories.  It is the perfect beverage to consume while fasting as it does not break your fast or impact your blood sugar levels. Drinking water has numerous health benefits, such as improving digestion, supporting metabolism, and promoting hydrated skin (4).

2. Unsweetened Black coffee

Black coffee is another popular drink for those fasting or following a ketogenic diet. It contains very few calories and has a negligible effect on blood sugar levels, making it an ideal beverage to consume while fasting.

See also
Can I Use Stevia While Fasting? Let’s Show You How to Sweeten a Fast

It does contain caffeine, which has been suggested to increase fat-burning and boost energy levels during fasting periods. The potential health benefits of caffeine include improved cognitive function, increased alertness, and protection against some chronic diseases (1).

Some debate exists on whether adding a splash of milk or cream to your coffee will break your fast. While it may not significantly affect weight loss, it may slightly impact ketosis for those following a strict ketogenic diet. Therefore, it’s best to consume straight black coffee during fasting periods.

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3. Unsweetened Green Tea

Green tea is another popular beverage for those practicing intermittent fasting or following a ketogenic diet. It contains few calories and has been suggested for a metabolism boost, as an aid in weight loss, and potentially to improve various health markers (2).

Studies have also suggested that green tea may promote better brain function (2) (6). Green tea contains caffeine, so it may provide benefits similar to black coffee during fasting periods.

However, some green tea varieties may have small amounts of carbohydrates, so it’s best to stick to unsweetened options.

4. Herbal Tea

Herbal teas, such as chamomile, peppermint, and ginger, are other great options for fasting periods. They contain few calories and offer numerous health benefits.

Chamomile tea has been shown to improve sleep and relaxation, while peppermint tea may aid in digestion and reduce bloating. Ginger tea is known for its anti-inflammatory properties and potential to alleviate nausea and digestive issues (12).

See also
Carve Out A Fasting Schedule To Meet Your Fitness Goals

These teas are a great way to add some flavor and variety to your fasting period, without breaking your fast or impacting ketosis, as long as you don’t add sugar in any form.

In a previous blog – Can You Drink Tea While Fasting – we discussed the best teas to consume while fasting and their potential benefits.

liquids to drink while fasting  

5. Sparkling Water

Sparkling water has become increasingly popular, especially for those looking for an alternative to plain water during fasting periods. It contains no calories or carbohydrates and can provide a refreshing change from regular water.

Studies even suggest that sparkling water may have some potential health benefits, such as improved digestion and reduced hunger levels (7).

Just make sure to choose a sugar-free option, as some flavored sparkling water brands may contain added sugars or artificial sweeteners, which could break your fast or affect ketosis.

Read more: Green Tea Intermittent Fasting: Benefits and Side Effects

6. Apple Cider Vinegar

Apple cider vinegar (ACV) has gained popularity in recent years for its potential health benefits. It has been suggested to improve digestion, aid in weight loss, and potentially reduce blood sugar levels (10).

While ACV does contain a few calories, studies suggest that consuming it during fasting periods may not break your fast or significantly impact ketosis. Just make sure to dilute it with water to avoid any negative effects on your stomach.

Some people suggest drinking this mixture with a straw to protect your teeth from the acidity in ACV. Additionally, adding a pinch of baking soda may help neutralize the acid and reduce potential stomach discomfort.

7. Black Coffee with MCT Oil

MCT oil, short for medium-chain triglyceride oil, is a popular supplement among those following a ketogenic diet. It contains fats that are able to be relatively quickly used for energy, making it an ideal addition to coffee during fasting periods (8).

See also
Intermittent Fasting Coffee: 7 Tips For Making It Perfect

The addition of MCT oil to black coffee can help increase feelings of satiety, boost energy levels, and support fat burning during fasting periods. Just make sure to stick to a small amount (1-2 tablespoons) to avoid consuming too many calories. Even if this combination may not kick you out of ketosis, consuming too many calories during your fasting period can still impact weight loss efforts.

Note that MCT oil may affect blood sugar levels in some.  Therefore, it’s best to monitor your body’s response and adjust accordingly.

In a previous blog: Zero Calorie Drinks for Intermittent Fasting , we discussed the importance of sticking to zero calorie drinks while fasting.

What Can I Put In My Water While Fasting?

Water is the only true zero calorie beverage, but you may want to add some flavor or nutrients to it during fasting periods. While there are a few options available, here are some safe additions that won’t break your fast or impact ketosis:

  • Lemon or Lime: Adding a squeeze of lemon or lime juice to your water can add some flavor and beneficial nutrients, such as vitamin C and antioxidants. Just make sure to avoid any added sweeteners.
  • Apple Cider Vinegar: As mentioned above, a small amount of ACV is a safe addition to water during fasting periods.
  • Salt: Adding a pinch of salt to your water can help replenish electrolytes lost through sweating or urination during fasting periods. This can help prevent dehydration and maintain proper hydration levels in your body (5).
  • Herbs or Spices: Adding herbs, such as mint or basil, or spices like cinnamon or ginger can add some flavor and potential health benefits to your water. Just make sure they are sugar-free options.
See also
An 18-Hour Fast May Be Just What Your Body Needs for Optimal Health

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What Should I Drink on a 7-Day Fast?

Most people on a 7 day fast stick to water, black coffee, and unsweetened tea as their primary beverages. However, some may choose to add other options, such as bone broth or vegetable broth, for added nutrients and electrolytes.

Drinking bone broth or vegetable broth during a 7-day fast may be advisable for the following reasons (3):

  • Nutrients and electrolytes: These broths contain some essential nutrients and electrolytes that may become depleted during a prolonged fast.
  • Easy digestion: Fasting can put stress on your digestive system, and consuming broth can provide some relief by offering easily digestible nutrients.
  • Appetite suppression: The warmth and savory flavors of broth can help reduce feelings of hunger and keep you satiated during a prolonged fast.
  • Variety: Adding broth to your fasting routine can provide some variety and make the experience more enjoyable.

Note that consuming broths during a fast may break your fast or impact ketosis, depending on the ingredients and amount consumed.

A 7-day fast is an extended period of time and should only be done under medical supervision. Make sure to consult with a healthcare professional before attempting a prolonged fast.

Check out our previous blog: What Can You Drink During Intermittent Fasting for more options and tips on beverages to include in your fasting routine.

liquids to drink while fasting

Will Coke Zero Break My Fast?

Coke Zero, like other diet sodas, contains zero calories and carbohydrates. However, it does contain artificial sweeteners, such as aspartame and acesulfame potassium (Ace-K).  These sweeteners have been shown to not impact blood sugar levels or insulin response in most individuals (11).

See also
Beat The Keto Flu: Symptoms, Prevention, And Cure

While some may argue that consuming artificial sweeteners during a fast may break the purpose of fasting, there is not enough evidence to suggest that they significantly impact weight loss or other potential benefits of fasting.

If your goal is to completely eliminate all food and drink except for water during your fast, then it would be best to avoid Coke Zero. This would be especially true in the case of a religious fast. Ultimately, the decision is up to personal preference and body response.

The effect of Coke Zero on ketosis during a fast will vary from person to person. Some individuals find that consuming artificial sweeteners affects their ketone levels, while others do not see any changes.

One downside of consuming diet sodas while fasting is that they may increase cravings for sweet foods, which can be counterproductive to weight loss efforts. It’s important to listen to your body and make decisions based on what works best for you. 

Read more: Intermittent Fasting and Running: A Winning Combination or a Terrible Mistake?


  • What Drinks Won’t Break Fast?

The following beverages are generally considered safe to consume during a fast, as long as they do not contain any added sugars or other ingredients that may impact insulin response:

  • Water
  • Black coffee
  • Unsweetened tea (such as green, black, or herbal tea)
  • Apple cider vinegar diluted in water
  • Lemon or lime juice squeezed in water
  • Do 20 Calories Break Fast?

20 calories may seem like a small amount, but it can have an impact on your fast. Depending on the source of those calories, they may cause an insulin response and break your fast or kick you out of ketosis.

To stay safe during a fast, it’s best to stick to zero calorie options or minimal amounts (less than 20 calories) of minimal calorie additions like apple cider vinegar or lemon juice.

  • What Drinks Have 0 Calories?

Plain water (still, sparkling, seltzer) is the only true zero calorie drink. Other options with negligible calories include black coffee and unsweetened tea. Some flavored water or sparkling beverages may also claim to have 0 calories, but it’s always important to check the label for any added sweeteners or flavors that may impact your fast.

  • Will 50 Calories Break a Fast?

50 calories is a significant amount and might break your fast, depending on the source of those calories. It’s best to avoid consuming any calorie-containing beverages or foods during a fast, as they may elicit an insulin response and potentially hinder your fasting goals.

The Bottom Line

While fasting, it’s crucial to stay hydrated and consume liquids that won’t break your fast or impact ketosis. Luckily, there are several options available that will satisfy your thirst while supporting your health goals. Remember to stick to zero calorie beverages like water, black coffee, green or herbal tea, and sugar-free sparkling water. 

Additionally, adding small amounts of MCT oil or apple cider vinegar can provide some added benefits during fasting periods. As always, it’s essential to listen to your body and choose the beverages that work best for you while staying true to your fasting goals. 


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. 9 Reasons Why (the Right Amount of) Coffee Is Good for You (n,d,
  2. Are There Health Benefits to Drinking Green Tea? (2023,
  3. Bone Broth: What It Does to Your Body (2023,
  4. Drinking water and your health (2023,
  5. Drinking Water: The Saltier The Better? (2019,
  6. Green tea improves cognitive function through reducing AD-pathology and improving anti-oxidative stress capacity in Chinese middle-aged and elderly people (2022,
  7. Is Sparkling Water Good for You? (2022,
  8. Is MCT Oil Worth the Hype? (2022,
  9. Ketosis (2022,
  10. The effect of apple cider vinegar on lipid profiles and glycemic parameters: a systematic review and meta-analysis of randomized clinical trials (2021,
  11. The Combined Effects of Aspartame and Acesulfame-K Blends on Appetite: A Systematic Review and Meta-Analysis of Randomized Clinical Trials (2022,
  12. The health benefits of 3 herbal teas (2021,
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