What drinks can be taken during fasting?

January 6, 2026 •

4 min read

According to a 2023 review published in Nutrients, intermittent fasting has been shown to offer benefits for weight management and body composition. To maximize these effects, it is crucial to know what drinks can be taken during fasting to stay hydrated and keep the body in a fasted state.

Quick Summary

This guide details the best calorie-free and low-calorie drink options for various fasting methods, including water, black coffee, and herbal teas. It also explains which beverages to avoid to prevent breaking your fast and disrupting metabolic benefits.

Key Points

Stay Hydrated: Water is the most essential drink during any fast to prevent dehydration and support bodily functions.
Choose Calorie-Free Options: Stick to beverages like plain water, sparkling water, black coffee, and unsweetened teas to avoid breaking your fast.
Avoid Added Sugars: Sugary drinks, including fruit juice and soda, will trigger an insulin response and negate the benefits of fasting.
Consider Electrolytes for Longer Fasts: If you are fasting for an extended period, zero-calorie electrolyte supplements can help replenish lost minerals and prevent fatigue or headaches.
Understand the Bone Broth Gray Area: Bone broth contains calories and protein, technically breaking a strict fast, but some use it for longer, modified fasts for its nutrient density.

Hydration is Key During Fasting

Staying hydrated is one of the most critical aspects of any fasting regimen, whether for intermittent, religious, or health reasons. Water is essential for maintaining bodily functions, regulating temperature, and transporting nutrients. When you are fasting, you lose electrolytes through urine and sweat, making proper fluid intake even more important. Dehydration can lead to fatigue, headaches, irritability, and sluggishness, which can undermine your fasting efforts.

Calorie-Free and Fast-Friendly Beverages

For most intermittent fasting protocols, the main rule is to avoid calorie intake during the fasting window. This means sticking to beverages that won't trigger an insulin response or disrupt metabolic processes.

Water and Infused Water

Plain Water: The ultimate fast-friendly drink. It has zero calories and is crucial for staying hydrated. Aim to drink plenty throughout your fasting window.
Sparkling Water: A good alternative to plain water, as long as it's unsweetened. It provides a satisfying fizz that can help curb cravings.
Flavored Water (Homemade): Infusing water with natural ingredients like lemon, lime, or cucumber can add flavor without adding significant calories. Be cautious with store-bought flavored waters, which can contain hidden sweeteners.

Coffee

Black Coffee: A popular choice for many fasters, as it contains virtually no calories. It can also help suppress appetite and provides a mild energy boost. However, avoid adding sugar, milk, or cream, as these will break your fast.

Tea

Unsweetened Tea: Green, black, or herbal teas are excellent options for fasting. They are calorie-free when consumed plain and offer antioxidants. Green tea, in particular, contains compounds that may support fat burning.
Herbal Tea: Caffeine-free herbal teas like chamomile, peppermint, or ginger can be soothing and hydrating. They are great for the evenings when you want a warm, relaxing drink.

Beverages to Approach with Caution

Some drinks exist in a gray area, and their appropriateness depends on the specific fasting goal. A purist approach to fasting aims for zero calories to maximize cellular repair (autophagy).

Electrolyte Powders

Zero-Calorie Electrolytes: Electrolyte imbalances can cause headaches, fatigue, and muscle cramps during fasting, especially longer fasts. Zero-calorie electrolyte powders or tablets can be a great way to replenish minerals without breaking a fast.
Electrolyte Drinks: Be very careful with pre-made electrolyte drinks. Many contain sugar and calories that will break your fast. Always check the nutrition label for added sugars and calories.

Bone Broth

Technically Breaks a Fast: As a broth derived from simmering animal bones, it contains protein and calories, and therefore will break a true fast. However, it can be a useful tool for longer fasts or modified fasting protocols, as it is nutrient-dense and helps with satiety. Some fasters use it to gently reintroduce nutrients to their system.

Drinks to Avoid Completely

To maintain a fasted state and reap the benefits, some beverages should be avoided entirely during your fasting window.

Sugary drinks: Fruit juices, sodas, and sports drinks contain high amounts of sugar and calories that will immediately break a fast.
Alcohol: Alcoholic beverages are not only high in calories but can also impair your body's ability to burn fat.
Milk and Dairy: Milk, cream, and other dairy products contain proteins and sugars that stimulate an insulin response, ending your fast.
Diet Drinks: Although zero-calorie, artificial sweeteners can trigger cravings and potentially cause a metabolic response that some fasters wish to avoid.

Comparison Table: Fast-Friendly Drinks


Drink	Caloric Content	Breaks Fast?	Notes
Plain Water	0 calories	No	Essential for hydration and weight loss.
Sparkling Water	0 calories	No	Unsweetened versions are a great calorie-free alternative.
Black Coffee	~2-5 calories	Generally no	Can suppress appetite and boost metabolism.
Unsweetened Tea	0 calories	No	Provides antioxidants and is very hydrating.
Zero-Calorie Electrolytes	0-5 calories	Generally no	Helps replenish minerals lost during longer fasts.
Bone Broth	40-50 calories per cup	Yes (strict fast)	Useful for modified fasts or breaking a fast gently.
Sugary Drinks	High calories	Yes	Causes an insulin spike and completely breaks a fast.
Alcohol	High calories	Yes	Disrupts metabolic processes and is dehydrating.

Conclusion: Making the Right Drink Choices

The right beverage choices can make or break your fasting success. The fundamental rule is to avoid caloric intake, especially sugar, which stimulates insulin and ends the fasted state. For most fasters, water, unsweetened tea, and black coffee are the safest and most beneficial choices. For longer fasts, incorporating zero-calorie electrolytes is a smart move to prevent dehydration and muscle cramps. Understanding these guidelines helps you maintain your health goals, whether you are fasting for weight loss, metabolic health, or cellular repair. By making informed decisions about what you drink, you can support your body's natural processes and achieve a more effective and comfortable fasting experience.

Visit Healthline for more details on what breaks a fast.

Frequently Asked Questions

Plain black coffee with no added sugar, milk, or cream will not break a fast. The minimal calories are considered insignificant for most intermittent fasting purposes and can help curb appetite. However, any additions will trigger an insulin response and end the fasted state.

Yes, unsweetened black, green, and herbal teas are excellent options during fasting. They are calorie-free and provide antioxidants and hydration. Just ensure you do not add sugar, milk, or cream.

A small squeeze of lemon in water is generally fine as it adds minimal calories. However, if you are a strict faster aiming for zero calories, some argue that even this can slightly affect your fast. For most, it's an acceptable way to add flavor.

Even though diet drinks are zero-calorie, some research suggests that artificial sweeteners can still trigger cravings or a metabolic response in some individuals. For the cleanest fast, it is best to stick to water, black coffee, or unsweetened tea.

Yes, bone broth contains calories and protein, so it will break a strict fast, especially if the goal is autophagy. Some people on modified fasts or those looking for nutrient support may still use it, but it should be noted it is not a zero-calorie option.

You can have electrolyte supplements as long as they are zero-calorie and do not contain sugar. This is particularly important for longer fasts to replenish minerals and prevent symptoms like headaches and fatigue.

Avoid all drinks with significant calories and sugars, including fruit juices, sodas, alcohol, milk, and cream. These will all break your fast and undermine your efforts.