What Can You Drink While Fasting? Complete Guide

March 11, 2025

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Fasting has become a popular health and wellness practice. Today, many individuals are adopting intermittent fasting to support weight loss and metabolic health. However, a common question or source of confusion is: what can you have while fasting? Some people are also confused about which beverages might accidentally break the fasting cycle. Many people wonder if consuming certain liquids interferes with their fasting benefits or disrupts fat-burning.

The rules of fasting revolve around calorie restriction. That is because consuming calories can trigger an insulin response and shift the body out of a fasting state. While some liquids are completely safe during fasting, others contain hidden ingredients that may break a fast. It is also crucial to consider hydration, as fasting reduces water intake from food. That makes it essential to drink enough fluids.

This article will explore which beverages are fasting-friendly, how many calories break a fast, and what to avoid. Whether you are practicing intermittent fasting, prolonged fasting, or religious fasting, this guide will help you make informed choices.

Understanding Intermittent Fasting

Intermittent fasting (IF) is an eating pattern that alternates between fasting and eating windows. Unlike traditional diets that focus on restricting calories or food types, IF emphasizes when you eat rather than what you eat. The primary goal of intermittent fasting is to extend the body’s fasting period. That allows the body to burn stored fat for energy instead of relying on glucose from recent meals.

There are several types of intermittent fasting, each varying in duration and structure:

16:8 Method: A common approach where you fast for 16 hours and eat within an 8-hour window.
18:6 Method: Extends fasting to 18 hours, further increasing fat-burning benefits.
5:2 Method: Involves eating normally for five days and reducing calorie intake (to about 500-600 calories) on two non-consecutive fasting days.
24-Hour Fast (OMAD): “One Meal a Day” fasting method, where you eat just one meal in 24 hours.
Alternate-Day Fasting: A cycle where you fast every other day, limiting calorie intake to 500 calories on fasting days.
Extended Fasting (48+ Hours): Prolonged fasting periods designed for deeper ketosis, autophagy, and cellular repair.

While intermittent fasting is popular for weight loss, improved insulin sensitivity, and metabolic health, it differs from religious fasting (such as Ramadan fasting). Certain religious fasting allows certain beverages and fasting foods during fasting hours. In the upcoming sections, we will focus on fasting for health and weight loss.

The Importance of Calories: How Many Calories Break a Fast?

When fasting, calories play a crucial role in determining whether your body remains in a fasted state. The general rule is any caloric intake can break a fast, as it triggers digestion, insulin production, and metabolic changes.

How Many Calories Break a Fast?

Strict fasting: Consuming any calories, even 1-2 calories from certain drinks, technically breaks a fast if the goal is complete autophagy and cellular repair.
Modified fasting: Some fasting regimens allow up to 50 calories, particularly from pure fats like MCT oil or butter in coffee, without significantly disrupting ketosis.
Protein and carbohydrates: Even a small amount (5-10 calories) coming from protein or carbs can elevate insulin levels. It will stop fat-burning and halt fasting benefits.

Why Do Calories Matter in Fasting?

Calories impact fasting in three key ways:

Insulin response: The primary goal of fasting is to keep insulin levels low. Even small amounts of sugar, dairy, or artificial sweeteners may spike insulin. That will disrupt fat oxidation.
Autophagy disruption: Fasting promotes cellular cleanup (autophagy), but consuming calories interrupts this process.
Metabolic shift: If the body detects incoming calories, it prioritizes digesting food over burning stored fat.

While some beverages, like water, black coffee, and herbal tea, contain zero calories and are fasting-friendly, others contain hidden ingredients that accidentally break a fast. Understanding the best fasting liquids is crucial for maintaining a successful fast.

What Can You Consume While Fasting? Do Fasting Liquids Matter?

Liquids play an essential role in fasting. Not only do they prevent dehydration, but they also help maintain energy levels, reduce hunger pangs, and support overall well-being. However, not all liquids are fasting-friendly. Some can cause an insulin spike, break ketosis, or trigger digestion, which may disrupt fasting benefits.

Why Do Liquids Matter in Fasting?

Hydration: Since food provides a significant amount of daily hydration, fasting increases the risk of dehydration. Hence, it is essential to increase water intake and electrolyte levels.
Electrolyte Balance: During fasting, the body excretes more sodium, potassium, and magnesium, which can cause fatigue, dizziness, or muscle cramps. Drinking electrolyte-rich liquids helps maintain balance.
Satiety and Energy: Some fasting liquids help curb hunger and boost mental clarity. That makes fasting easier to sustain.

By following these principles, you can optimize your fasting experience while staying hydrated and energized.

What Can You Have When Fasting: Intermittent Fasting Drinks

Fasting does not mean complete deprivation. While solid foods are off-limits, several beverages can keep you hydrated and even support fasting benefits. The key is to choose drinks that do not trigger an insulin response or interrupt ketosis. But does water break a fast? What about coffee or herbal tea? Let us explore the best fasting-friendly liquids and how they support overall health.

1. Water: The Ultimate Fasting Drink

Water is essential for hydration and is 100% fasting-friendly. Drinking plenty of water during fasting prevents dehydration, fatigue, and headaches. If plain water feels boring, you can add a slice of lemon or cucumber without disrupting fasting benefits. Does lemon water break a fast? No, as long as there is no added sugar.

Allowed: Plain water, sparkling water, mineral water
Avoid: Flavored or sweetened water with added sugars or artificial sweeteners

2. Black Coffee: A Fasting Booster

Coffee is one of the most popular fasting drinks. It contains zero calories and may enhance fat burning by stimulating metabolism. Research suggests that caffeine promotes fat oxidation and may increase autophagy, the body’s natural repair process. However, adding sugar, milk, or flavored syrups will break a fast.

Allowed: Black coffee (no sugar, milk, or cream)
Avoid: Lattes, cappuccinos, flavored coffee, coffee with sweeteners

3. Green Tea: Metabolism and Antioxidant Support

Green tea is an excellent fasting drink. It provides antioxidants and metabolism-boosting catechins. It also supports fat oxidation and may improve insulin sensitivity. Some studies show that green tea catechins enhance weight loss. That makes it a great addition to intermittent fasting.

Allowed: Plain green tea, black tea, white tea, herbal tea
Avoid: Sweetened teas, premade bottled teas, teas with added milk or sugar

4. Herbal Tea: A Caffeine-Free Alternative

Herbal teas such as peppermint, ginger, and chamomile do not contain calories and offer various health benefits. They aid digestion, relieve bloating, and reduce cravings. Ginger tea, for instance, is known to support gut health. So, for those asking, ‘If I am fasting, what foods are good for gut health?’ herbal tea is an excellent option.

Allowed: Plain herbal teas without sweeteners
Avoid: Flavored teas, teas with milk and fruit juices.

5. Sparkling Water: A Refreshing Option

Sparkling water is a great way to stay hydrated while fasting. It contains no calories or artificial additives and can reduce hunger by creating a feeling of fullness. However, always choose unsweetened versions.

Allowed: Plain sparkling water, club soda
Avoid: Sweetened or flavored carbonated drinks

6. Apple Cider Vinegar (ACV): A Fasting-Friendly Drink

People often consume apple cider vinegar during fasting due to its potential benefits for digestion and appetite control. Research suggests that ACV may support blood sugar regulation and reduce cravings. However, you must always dilute it with water if you do not want to break your fast.

Allowed: Diluted apple cider vinegar (1 tbsp in a glass of water)
Avoid: ACV drinks with honey or sweeteners

7. Electrolyte Water: Preventing Dehydration

During fasting, the body loses essential minerals such as sodium, potassium, and magnesium. Consuming unsweetened electrolyte water helps maintain hydration and prevents fatigue, muscle cramps, and dizziness.

Allowed: Electrolyte-infused water (no sugar or artificial sweeteners)
Avoid: Sports drinks, flavored electrolyte drinks with added sugars

Intermittent Fasting: Drinks to Avoid While Fasting

Not all beverages are suitable for fasting. Some drinks spike insulin levels, stimulate digestion, or contain hidden calories that can break your fast. Here is a list of drinks to avoid while fasting and why they interfere with fasting benefits.

1. Sugary Beverages (Sodas & Fruit Juices)

Sodas, fruit juices, and flavored drinks are high in sugar, which triggers an insulin response and halts fat burning. Even natural fruit juices contain fructose, which breaks a fast and disrupts ketosis.

Avoid: Regular sodas, fruit juices, energy drinks, sweetened iced teas

2. Diet Sodas & Artificially Sweetened Drinks

While diet sodas contain zero calories, they include artificial sweeteners that may stimulate insulin secretion and increase cravings. Research suggests that artificial sweeteners can disrupt gut bacteria, negatively affecting metabolic health.

Avoid: Diet sodas, flavored sparkling waters with sweeteners, sugar-free energy drinks

3. Milk & Dairy-Based Beverages

Milk, cream, and other dairy-based drinks contain lactose, a natural sugar that raises insulin levels. Even small amounts of milk in coffee can disrupt ketosis and halt fasting benefits.

Avoid: Milk, creamers, lattes, cappuccinos, milk-based protein shakes

4. Alcohol

Alcohol is high in empty calories and can negatively affect metabolism. Drinking alcohol on an empty stomach may also cause dizziness, dehydration, and impaired digestion.

Avoid: Beer, wine, cocktails, spirits

5. Bone Broth

Although nutrient-rich, bone broth contains proteins and amino acids, which stimulate digestion and insulin secretion. While it is beneficial for breaking a fast, you should not consume it during fasting hours.

Avoid: Bone broth, protein broths, soups

Best Foods to Break a Fast

Breaking a fast correctly is just as important as fasting itself. After fasting for several hours, the digestive system is in a sensitive state. Consuming heavy or processed foods can cause bloating, indigestion, and blood sugar spikes.

Best Foods to Eat After Fasting

Smoothies: Easy to digest and packed with nutrients. A low-sugar, protein-rich smoothie is ideal for breaking a fast.
Dried Fruits (Dates, Apricots): Rich in fiber and natural sugars, dates provide a gentle energy boost without spiking insulin.
Soups (Broth-Based): Light soups with vegetables and lean protein help ease digestion. Avoid heavy cream-based soups.
Cooked Vegetables (Sweet Potatoes, Zucchini): Soft-cooked vegetables are gentle on the stomach and rich in fiber.
Fermented Foods (Yogurt, Kefir): Probiotic-rich foods support gut health and aid digestion after fasting.
Healthy Fats (Avocados, Eggs, Nuts): Fats provide long-lasting energy without spiking blood sugar.

What to Avoid When Breaking a Fast

Processed Foods (Fast Food, Sugary Snacks): Can cause blood sugar crashes and digestive discomfort.
High-Fiber Foods (Raw Veggies, Beans, Whole Grains): May cause bloating due to the digestive system being inactive.
Large, Heavy Meals: Overeating can stress digestion and cause fatigue after a fast.

HealthifyMe Note

Fasting is not a one-size-fits-all approach. While some people experience incredible benefits from intermittent fasting, it is essential to recognize that not all fasting methods suit every individual. Your body’s needs, metabolism, and lifestyle play a crucial role in determining what works best for you. There is often confusion about what you can eat and drink while fasting, but sticking to the fundamentals will help you maximize its benefits. The fundamentals are hydration, mindful food choices, and sustainable fasting schedules. It is equally important to listen to your body. If fasting leaves you feeling drained or unwell, it may not be the right approach for you. The key is balance.

Instead of following extreme diets, opt for a structured and science-backed fasting plan. Consulting a health expert or a nutritionist before starting any fasting regimen can help you tailor an approach that aligns with your goals and health conditions.

The Final Word

Fasting, when done correctly, can offer various health benefits, from weight loss to better metabolic health. However, success in fasting does not just depend on the duration—it depends on making smart food and drink choices. The beverages you consume during fasting can significantly impact your progress. Knowing what to drink while fasting ensures that you stay in a fasted state without disrupting ketosis or insulin sensitivity. Similarly, breaking a fast with the right foods is crucial to maintaining energy levels and avoiding digestive discomfort. The best results come when fasting is paired with a nutritious, well-balanced diet and an active lifestyle.

If you are unsure about what to eat and drink or how to plan your fasting journey, HealthifyMe’s Health AI Plans can provide a personalized guide. This AI-powered system helps you track your fasting, suggests beverages and foods suited to your fasting type, and even alerts you to foods and drinks that might break your fast. With expert insights and real-time data, you can make informed decisions and stay on track with your health goals.

Start your fasting journey the smart way—with guidance, knowledge, and a sustainable approach.

Frequently Asked Questions (FAQs)

Q: What can you drink when fasting?

A: You can drink water, black coffee, green tea, herbal tea, apple cider vinegar (diluted), and unsweetened electrolyte water during fasting. These drinks do not contain calories and help maintain hydration, prevent cravings, and support metabolic functions. However, you should avoid sweetened beverages, milk, and high-calorie drinks, as they can break your fast.

Q: How many calories can break a fast?

A: A strict fast means consuming zero calories to maintain the fasting benefits. However, some fasting approaches allow up to 50 calories from fat-based sources, such as MCT oil or butter in coffee, without significantly disrupting ketosis. Any intake of protein, carbohydrates, or sugars, even in small amounts, can spike insulin levels and break a fast.

Q: What should you eat to break a fast?

A: The best foods to break a fast include smoothies, bone broth, cooked vegetables, fermented foods, healthy fats (like avocado and eggs), and easily digestible proteins. These foods ease digestion, replenish nutrients, and stabilize blood sugar levels. Avoid highly processed, sugary, or fried foods, as they can lead to bloating and blood sugar spikes.

Q: What to drink while fasting for maximum benefits?

A: For maximum benefits, stick to hydrating and metabolism-boosting drinks like water, black coffee, green tea, and herbal teas. These drinks help curb hunger, improve mental clarity, and support fat burning without triggering an insulin response. Electrolyte water can also be beneficial if fasting for extended periods to prevent dehydration.

Q: Does intermittent fasting 16:8 really work for weight loss?

A: Yes, the 16:8 intermittent fasting method can be effective for weight loss when combined with a balanced diet and regular exercise. This fasting schedule extends the body’s natural fat-burning phase and helps regulate insulin levels. However, weight loss depends on caloric intake and food quality during eating windows.

Q: Can I drink lemon water during fasting?

A: Yes, lemon water does not break a fast as long as it contains no added sugars or other caloric ingredients. A slice of lemon in water provides a refreshing flavor, supports digestion, and offers a dose of vitamin C without disrupting fasting benefits. However, avoid prepackaged lemon drinks that may contain hidden sugars.

Q: What happens if I drink milk or juice while fasting?

A: Milk and fruit juices contain sugars and carbohydrates, which spike insulin levels and shift your body out of a fasting state. Even a small amount of milk in coffee can disrupt ketosis. If you need a fasting-friendly alternative, consider unsweetened almond milk or diluted apple cider vinegar, but always check for hidden sugars.