Can you have infused water when fasting? A guide to staying hydrated without breaking your fast

October 21, 2025 •

5 min read

Intermittent fasting is a popular dietary pattern, with up to one-third of US adults reportedly trying it for various health benefits. A common question that arises is, can you have infused water when fasting? The good news is that, for most fasting protocols, the answer is yes, with a few important caveats.

Quick Summary

Infused water with low-calorie ingredients like lemon, cucumber, and herbs is acceptable during many fasts. The key is avoiding added sugars or significant calories that would trigger an insulin response. It helps with hydration and can curb cravings, but strict fasters may opt for plain water only.

Key Points

Low-Calorie Rule: Any beverage with significant calories or sugar will break a fast, so choose your infusion ingredients carefully to stay within a minimal calorie range.
Safe Infusion Ingredients: Low-sugar items like lemon slices, cucumber, mint, and ginger are generally acceptable for flavoring water without compromising most intermittent fasts.
Avoid Sugars and Sweeteners: Steer clear of fruit juices, sugary drinks, and artificial sweeteners, as they can trigger an insulin response and disrupt the fasting state.
Stay Hydrated: Proper hydration is crucial during fasting to prevent dehydration, manage hunger, and maintain energy levels.
Mind Your Fasting Type: Consider your specific fasting goals; while intermittent fasting allows for minimal caloric intake, a strict "clean fast" means only plain water.
Don't Consume the Solids: To keep calories to a minimum, drink only the infused water and avoid eating the fruit or herb solids.
Listen to Your Body: Pay attention to how your body reacts to infused water; if it increases your hunger, you may prefer sticking to plain water.

Understanding the Fasting Principle

At its core, fasting involves a period of voluntary abstinence from consuming food or calorie-containing beverages. The primary metabolic goal of intermittent fasting for many is to maintain a state where the body is not producing insulin in response to food intake. This allows the body to enter a state of ketosis, where it burns stored fat for energy, and potentially promotes cellular repair processes like autophagy.

Experts agree that consuming any significant amount of calories, particularly from carbohydrates and protein, will trigger an insulin response and effectively end the fasted state. The distinction between a "clean fast" (zero calories) and a "dirty fast" (minimal calories, often under 50) is important, as individual goals determine the level of strictness required. For most common intermittent fasting methods, such as the 16:8 or 5:2, a small amount of low-calorie flavor is generally acceptable.

The Role of Infused Water in a Fast

Infused water is made by adding fruits, vegetables, or herbs to water, allowing the flavors and trace nutrients to seep out without adding significant calories or sugars. The safety of infused water during a fast hinges on the quantity and type of ingredients used, and crucially, whether you consume the ingredients themselves.

For a general intermittent fast, a few slices of lemon or cucumber will not provide enough calories or sugar to break the fast. However, if you squeeze a significant amount of fruit juice or use sweet fruits like berries or mango, the caloric and sugar content could become an issue, depending on your fasting goals. The practice of a "clean fast" would exclude even these trace calories, while those with more flexible goals can enjoy them in moderation.

Fast-Friendly Infusion Ingredients

Here are some of the safest ingredients to use for infusing water during a fast:

Lemon and Lime: A small squeeze or a few slices add flavor and Vitamin C with negligible calories, and won't disrupt most intermittent fasts.
Cucumber: Slices of cucumber impart a fresh, cooling taste and are essentially calorie-free when infused.
Mint: A handful of mint leaves provides a refreshing taste and can also aid digestion.
Ginger: Thin slices of ginger add a spicy kick and have anti-inflammatory benefits with minimal calories.
Cinnamon Sticks: For a warm, spiced flavor, whole cinnamon sticks are a calorie-free option.

Hydration is Key to a Successful Fast

Staying hydrated is one of the most critical aspects of any fasting protocol and is even more important than usual because you are not getting water from solid foods. When you fast, your body breaks down stored glycogen, releasing associated water, which can lead to rapid fluid loss and potential dehydration. Drinking sufficient water helps to:

Curb Hunger: Thirst is often mistaken for hunger. A glass of water can help determine if you are truly hungry.
Maintain Energy Levels: Dehydration can cause fatigue, headaches, and low energy. Staying hydrated supports cognitive function and prevents these symptoms.
Replenish Electrolytes: Longer fasts may cause a loss of electrolytes. Adding a pinch of mineral-rich salt to your water can help maintain balance.

Fasting-Friendly Beverages Comparison


Beverage	Calories	Fast-Friendly?	Notes
Plain Water	0	Yes	The gold standard for hydration during a fast.
Infused Water (Safe)	Negligible	Yes (for most)	Using low-sugar ingredients like lemon, cucumber, or mint, and avoiding the pulp.
Black Coffee	~5	Yes	Acceptable as long as no milk, sugar, or cream is added.
Herbal Tea (Unsweetened)	Negligible	Yes	Must be plain herbal tea without fruit extracts or sugars.
Fruit Juice	High	No	High in sugar and calories, will break a fast.
Soda (Regular)	High	No	Contains high sugar levels and is forbidden during a fast.
Soda (Diet)	0	No (Generally)	Artificial sweeteners can cause an insulin response in some people, disrupting the metabolic state.

Avoiding the Pitfalls of Infused Water

To ensure your infused water doesn't break your fast, follow these best practices:

Don't Eat the Fruit: Never consume the fruit or vegetable slices, as this introduces solid food and calories. The goal is a subtle flavor, not nourishment.
Use Fresh Ingredients: Avoid bottled or commercially prepared flavored waters, which often contain hidden sugars, calories, or artificial sweeteners that can trigger an insulin response.
Watch the Quantity: While a slice of lemon is fine, adding an entire glass of blended berries will introduce enough calories to break your fast. Stick to minimal amounts for flavor.
Limit Infusion Time: For sweeter ingredients like berries, limiting the infusion time can reduce the amount of sugar extracted into the water. Remove ingredients after a few hours.

Conclusion

For those practicing intermittent fasting, enjoying infused water is a great strategy to make hydration more palatable and to potentially curb cravings without derailing your progress. As long as you stick to low-calorie, fresh ingredients like lemon, cucumber, mint, and ginger, and avoid consuming the fruit pulp or adding any sweeteners, you can enjoy this refreshing beverage during your fasting window. Remember that individual goals matter, and for a strict "clean fast" or religious fast, only plain water may be permitted. Always listen to your body and adjust your approach based on your specific needs and goals. For those with medical conditions, it's always wise to consult a healthcare professional before starting any new fasting protocol.

Recommended Fasting Drink

One excellent, fast-friendly drink is a simple cucumber and mint infusion. Just slice a cucumber and add some fresh mint leaves to a pitcher of water. Let it infuse for an hour or two in the fridge. This provides a refreshing taste with no calories to compromise your fast.

Potential Downsides of Infused Water

While generally safe, there are minor considerations. Consistent consumption of acidic fruits like lemon could, over time, affect tooth enamel. Some individuals might also find that the flavor can stimulate their digestive system and increase hunger pangs. However, these are typically minor issues for most and can be mitigated by rinsing your mouth with plain water after drinking or by switching to less-acidic infusions.

Infused Water vs. Plain Water During a Fast

While plain water is the ultimate "clean fast" beverage, infused water offers variety and a pleasant taste that can make staying hydrated easier for some. The choice often comes down to personal preference and the strictness of your fasting protocol. For those struggling with plain water fatigue, a safe infusion can be a game-changer, helping you stick to your fasting plan and reap its full benefits.

Conclusion on Fast-Friendly Hydration

Incorporating infused water into your fasting routine is a simple and effective way to enhance hydration and make the process more enjoyable. By being mindful of your ingredients and avoiding high-calorie additions, you can successfully integrate flavorful water into your lifestyle without breaking your fast. Prioritizing hydration, in whatever form works best for you, is key to a comfortable and successful fasting journey.

Frequently Asked Questions

No, a slice or small squeeze of lemon is generally acceptable and will not break a fast. It contains a negligible amount of calories and won't cause an insulin spike.

For most intermittent fasting, a few berries for flavor are acceptable, but you should not eat them. Using a handful of very sweet fruit might add enough sugar to break a clean fast.

It is best to avoid artificial sweeteners during a fast. Even though they are calorie-free, some studies suggest they can still trigger an insulin response in some people and may interfere with fasting benefits.

Yes, infusions with vegetables like cucumber are a great, calorie-free option for flavor during a fast. Just be sure not to eat the slices.

Yes. Fasting guidelines for medical procedures are often much stricter, prohibiting all fluids except for specific clear liquids in a controlled timeframe. Always follow your doctor's instructions in this case.

Excellent, calorie-free herb options include mint, rosemary, basil, and ginger. These can add refreshing and digestive-aid properties to your water without breaking your fast.

You should drink a sufficient amount of water to stay hydrated, but there is no need to overdo it. Drinking excessively can potentially lead to an electrolyte imbalance.

You should only use homemade infused water with fresh ingredients. Most bottled flavored waters contain added sugars, flavorings, or artificial sweeteners that will break your fast.