What Should You Drink While Fasting for Optimal Results?

January 3, 2026 •

4 min read

According to a 2023 review, intermittent fasting has been shown to offer significant health benefits, including weight management and improved insulin sensitivity. To maximize these positive effects, it is crucial to know what should you drink while fasting to stay hydrated without breaking your fast.

Quick Summary

An exploration of fasting-approved beverages, detailing safe options like water, unsweetened tea, and black coffee. It covers how to maintain hydration and electrolyte balance, distinguishes between strict and modified fasting, and advises on drinks to avoid for optimal fasting outcomes.

Key Points

Plain Water is Essential: The best choice for hydration is calorie-free water, including both still and sparkling versions, to prevent dehydration and support bodily functions.
Black Coffee is Safe: Plain black coffee, without any additives like sugar, milk, or sweeteners, will not break a fast and can help suppress appetite.
Unsweetened Tea is Permissible: Unsweetened green, black, and herbal teas are good, calorie-free options, offering antioxidants and other benefits during a fast.
Bone Broth for Modified Fasts: While technically breaking a clean fast, bone broth is useful for modified fasts as it provides electrolytes and satiety.
Avoid Sugary and High-Calorie Drinks: Any beverage with sugar, milk, cream, or other high-calorie ingredients will trigger an insulin response and break your fast.
Exercise Caution with Diet Sodas: The artificial sweeteners in diet sodas may have subtle metabolic effects and are best avoided, especially for those pursuing strict fasting benefits.
Replenish Electrolytes on Longer Fasts: For fasts longer than 24 hours, consider zero-calorie electrolyte supplements or a pinch of salt in water to prevent imbalances and fatigue.

Fasting has become a popular practice for numerous health benefits, from weight loss to cellular repair via autophagy. However, sustaining a fast requires careful attention to hydration. The wrong drink can prematurely end your fasted state by triggering an insulin response, while the right choices can support your goals and prevent dehydration.

The Best Hydrating Drinks for a Clean Fast

For those adhering to a strict or "clean" fast—where the goal is zero caloric intake—the options are straightforward. The key is to consume beverages that do not contain calories or sugar, preventing an insulin spike.

Plain Water: Still and sparkling water are the gold standards for hydration during a fast. Water has zero calories and is essential for all bodily functions, including flushing out toxins and maintaining fluid balance. It is especially important to drink plenty of water to counter the diuretic effect that can occur during fasting.
Black Coffee: When consumed without sugar, milk, cream, or other additives, black coffee contains a negligible amount of calories (about 3-5 per cup) and will not break a fast. Caffeine can also help suppress appetite and provide an energy boost, which can make fasting easier for some.
Unsweetened Tea: Green, black, and herbal teas are excellent, calorie-free choices, as long as no sugar, honey, or milk is added. Herbal infusions like peppermint or chamomile can help soothe the stomach and reduce cravings. Green tea is particularly noted for its antioxidant content.

Navigating Modified Fasting with Other Beverages

Some fasting methods, often called "dirty fasting," allow for a minimal caloric intake to make the process more manageable. These are typically used by individuals focused more on calorie restriction and weight management rather than maximizing autophagy.

Can you drink bone broth while fasting?

This is a common question, and the answer is nuanced. True, zero-calorie fasts are broken by bone broth, which contains a small number of calories from protein and fat. However, it is an excellent option for modified fasts, especially longer ones, for several reasons:

Electrolyte Replenishment: Bone broth is rich in essential electrolytes like sodium, potassium, and magnesium, which are rapidly depleted during fasting. Replenishing these can prevent symptoms like headaches, fatigue, and muscle cramps, often referred to as the "keto flu".
Satiety: The protein and gelatin content can help you feel full, making it easier to manage hunger pangs during a fast.
Gut Support: It provides amino acids like glycine that can help decrease inflammation and support gut health.

The Electrolyte Solution

Electrolytes are crucial for proper hydration, especially on longer fasts where water and minerals are lost more quickly. Zero-calorie electrolyte powders or tablets without sugar are a fasting-safe way to replenish these minerals and alleviate fatigue. A simple homemade option is to add a pinch of Himalayan salt to your water for trace minerals.

The Debate Over Diet Sodas

The zero-calorie claim of diet sodas leads many to wonder if they are acceptable. While technically not adding calories, the artificial sweeteners can be problematic. Some individuals may experience a physiological response that triggers insulin release, potentially interfering with fasting benefits. These sweeteners can also increase sugar cravings and negatively impact gut health. For these reasons, many experts recommend avoiding them altogether during a fast.

What to Avoid While Fasting

To ensure you maintain your fasted state and achieve your health goals, it's critical to avoid certain types of beverages completely during your fasting window. The presence of calories, sugar, or high levels of carbohydrates will inevitably break your fast.

Sugary drinks: This includes regular soda, fruit juices, sweetened iced tea, and energy drinks. The high sugar content will immediately spike your insulin levels.
Milk and Cream: Dairy products contain sugars and proteins that trigger an insulin response. Even a small splash in your coffee can interrupt a strict fast.
Alcohol: Alcoholic beverages are high in calories and should be avoided entirely during fasting. They can disrupt metabolic processes and hinder fat burning.
Sweetened Nut Milks: Many almond or soy milks contain added sugars and calories that will break a fast. Always read the nutrition label carefully.

Comparison of Fasting Beverages


Beverage Type	Fasting Compatibility	Key Benefits	Considerations
Plain Water (Still & Sparkling)	Optimal (Clean Fast)	Zero calories, essential for all bodily functions, flushes toxins.	Most fundamental for hydration.
Black Coffee (Unsweetened)	Optimal (Clean Fast)	Contains antioxidants, provides energy boost, can suppress appetite.	Avoid if sensitive to caffeine or have stomach issues; can dehydrate slightly.
Unsweetened Tea (Herbal, Green, Black)	Optimal (Clean Fast)	Rich in antioxidants, can be calming (herbal) or energizing (green/black).	Avoid with additives; ensure herbal is unsweetened.
Bone Broth	Modified Fast	Electrolytes, satiating protein, gut-healing amino acids.	Technically breaks a clean fast due to low calories.
Zero-Calorie Electrolytes	Clean Fast (Most)	Replenishes vital minerals (sodium, potassium, magnesium).	Ensure no sugar or artificial sweeteners; check ingredients carefully.
Diet Soda	Controversial	Zero calories from a strict perspective.	Artificial sweeteners may trigger insulin response, increase cravings, and impact gut health.

Conclusion

For those seeking the purest form of fasting and its associated benefits, sticking to zero-calorie, zero-additive beverages like plain water, black coffee, and unsweetened teas is the safest and most effective approach. For modified fasting protocols, bone broth and zero-sugar electrolyte supplements can be beneficial for managing hunger and maintaining electrolyte balance. Regardless of your method, staying hydrated is a non-negotiable aspect of any fasting regimen to support overall health and well-being. Always listen to your body and its signals, as individual tolerance can vary. Consulting with a healthcare professional before beginning any new fasting routine is recommended.

Visit Healthline for more detailed information on drinking water while fasting.

Frequently Asked Questions

No, adding cream, milk, or sugar to your coffee provides calories and will trigger an insulin response, effectively breaking your fast.

Zero-calorie flavored water that uses natural essences and contains no artificial sweeteners or sugars is generally safe. However, artificial sweeteners in some brands may cause a minor insulin response in some people, so plain water is always the safest option.

For a strict zero-calorie fast, bone broth is not approved as it contains protein and fat. However, it is an excellent source of electrolytes and is often incorporated into modified fasts to aid with hunger and hydration.

The best electrolytes for fasting are zero-calorie and sugar-free options. These can be found in powdered supplements or by adding a pinch of Himalayan salt to your water.

Yes, unsweetened herbal teas are safe to drink while fasting. Herbal infusions like chamomile, ginger, or peppermint contain no calories and can offer additional benefits like soothing digestion.

While diet soda contains zero calories, the artificial sweeteners can confuse your body, potentially causing an insulin response and increasing cravings for sugar. Most experts recommend avoiding it for optimal results.

Signs of dehydration during a fast include headaches, fatigue, dizziness, and muscle cramps. Replenishing your water and electrolyte intake is crucial if you experience these symptoms.