Yes. You can drink water while intermittent fasting. Water has no calories, and it is the simplest fasting-window drink for most people.[1] Intermittent fasting usually means avoiding calorie-containing foods and drinks during the fasting window, not avoiding water.
For a clean fasting window, keep drinks simple: plain water, sparkling water, black coffee, or unsweetened tea are common choices.[1][2] Sweetened drinks, juice, alcohol, milk, cream, and calorie-containing add-ins fit better in the eating window.
Key takeaways
- Water is allowed during intermittent fasting and has no calories.[1]
- Plain still water, sparkling water, and seltzer are simple options.[1]
- Black coffee and unsweetened tea are also common fasting-window choices.[2]
- Drinks with sugar, milk, cream, alcohol, juice, or calories are not clean fasting-window choices.
- If you have a medical condition or take medications, fasting rules should not override clinical guidance.[3]
Table of Contents
Why water is allowed during fasting
Water does not add calories, so it does not turn the fasting window into an eating window.[1] It can also make a fasting routine easier to follow because thirst can feel like hunger for some people.
Intermittent fasting changes when you eat; it does not mean avoiding fluids. In fact, fasting plans that restrict water are a different and higher-risk topic, and they should not be treated as standard intermittent fasting.
What drinks fit a fasting window
The cleanest approach is to choose drinks with no meaningful calories and no sweetened add-ins.
| Drink | Fasting-window fit | Notes |
|---|---|---|
| Plain water | Good default | No calories |
| Sparkling water or seltzer | Usually fits | Choose unsweetened versions |
| Black coffee | Common option | Avoid sugar, cream, milk, or syrups |
| Unsweetened tea | Common option | Avoid honey, sugar, or milk |
| Flavored water | Depends | Check calories, sweeteners, and ingredients |
| Diet drinks | Depends | Few or no calories does not make them the strongest default |
Non-sugar sweeteners may add few or no calories, but that does not automatically make every diet drink a strong fasting default.[4]
For a broader drink guide, read What other drinks can you drink?.
What to avoid during the fasting window
During the fasting window, avoid drinks or add-ins that contain calories or sugar.
Common examples include:
- Soda, sweet tea, lemonade, and energy drinks with sugar
- Juice or smoothies
- Alcohol
- Coffee with sugar, cream, milk, syrups, collagen, butter, or MCT oil
- Tea with honey, sugar, or milk
- Sports drinks with calories
These choices can still fit your overall day if you include them during the eating window, but they are not clean fasting-window choices.
How much water should you drink
There is no single water target that fits everyone. Thirst, climate, body size, activity, medications, and medical conditions can all change fluid needs.
A practical approach is to:
- Keep water available during the fasting window
- Drink before you feel overly thirsty
- Notice signs that you may need to stop or adjust, such as dizziness, weakness, or symptoms that feel unsafe
- Get medical guidance if medications, kidney disease, diabetes, pregnancy, breastfeeding, or other medical issues affect hydration or fasting decisions
Do not use water as a way to push through a fast that feels unsafe.
When water rules are not enough
Water can support a fasting routine, but it does not make fasting appropriate for everyone. Do not treat fasting as self-guided if medications, diabetes, kidney disease, pregnancy, breastfeeding, underweight status, recovery from illness or surgery, or eating-disorder risk are part of the picture.[3]
Side effects can include tiredness, dizziness, headaches, mood changes, constipation, diabetes management issues, and menstrual effects.[5] If symptoms are persistent, severe, or feel unsafe, stop or shorten the fast and get qualified guidance.
FAQ
Can you drink water on intermittent fasting?
Yes. Water has no calories and is the simplest drink during the fasting window.[1]
Can you drink sparkling water while intermittent fasting?
Plain sparkling water or seltzer can fit because they are low-calorie choices.[1] Check labels if the drink is flavored or sweetened.
Does lemon water break a fast?
A small squeeze of lemon in water is unlikely to add many calories, but strict fasting rules vary. If you want the cleanest fasting window, choose plain water.
Can you drink coffee while intermittent fasting?
Black coffee is a common fasting-window option.[2] Coffee with sugar, cream, milk, syrups, or other calorie-containing add-ins belongs in the eating window.
What can I eat after fasting?
This article focuses on drinks. For food options during the eating window, read What can I eat while intermittent fasting?.
Bottom line
Water is allowed during intermittent fasting and is the simplest fasting-window drink. Plain water, sparkling water, black coffee, and unsweetened tea are practical defaults. Keep sweetened drinks, juice, alcohol, milk, cream, and calorie-containing add-ins in the eating window.
Medical disclaimer
This article is for general educational purposes only and is not medical advice. Speak with a qualified health professional before starting or changing a fasting routine if you have a medical condition, take medications, are pregnant or breastfeeding, are underweight, have eating-disorder history or risk, or develop symptoms that concern you.
References
- CDC. About Water and Healthier Drinks
- Johns Hopkins Medicine. Intermittent Fasting: What Is It, And How Does It Work?
- Cleveland Clinic. 6 Tips for Fasting Safely
- U.S. Food & Drug Administration. Aspartame and Other Sweeteners in Food
- Mayo Clinic. Intermittent fasting: What are the benefits?