Yes, you can drink water during intermittent fasting. Plain water does not add calories, and staying hydrated can make a fasting routine easier to repeat. The main thing to avoid is turning a simple fasting window into a dry fast or a rigid water rule.
Key takeaways
- Plain water is the simplest drink during a fasting window.
- Sparkling water and unsweetened flavored water may fit for many people if they have no calories.
- Sugary drinks, juice, sweetened coffee drinks, and alcohol are not fasting-window drinks.
- Drinking enough water matters because dehydration can affect thinking, mood, body temperature, digestion, and kidney stone risk [2].
- If fasting comes with dizziness, headaches, unusual fatigue, or other symptoms, shorten the fast or get guidance [3].
Water during intermittent fasting is different from water-only fasting
Intermittent fasting usually means alternating eating periods and fasting periods. Common versions include time-restricted eating, such as 14:10 or 16:8, and other schedules such as 5:2 [1].
Drinking water during a fasting window is not the same thing as doing a water-only fast for a full day or longer. Longer fasts are not automatically better, and some longer fasts may be dangerous for some people [1].
For most beginners, the practical goal is simple: keep your regular fasting window hydrated while eating enough nutritious food during your eating window.
What you can usually drink during a fasting window
Plain water is the safest default. It has no calories and supports normal body functions.
Other low- or no-calorie drinks may fit depending on your fasting style and personal tolerance. The CDC lists plain coffee, tea, sparkling water, seltzer, and flavored waters among low- or no-calorie beverage options [2].
If your goal is a clean, simple fasting window, keep it basic:
- plain water
- sparkling water with no sugar
- unsweetened tea
- black coffee, if you tolerate caffeine
If a drink contains sugar, cream, milk, juice, protein, or calories, count it as part of the eating window.
What to avoid during the fasting window
Avoid drinks that make the fasting window less clear or harder to manage:
- soda
- sweetened tea
- sweetened coffee drinks
- juice
- smoothies
- sports drinks with sugar
- alcohol
- creamers or milk added to coffee
This does not mean those drinks are all equally unhealthy. It means they do not fit a fasting window if your goal is to keep the window calorie-free.
How much water should you drink?
There is no single water target that works for everyone. Daily water needs vary by age, sex, activity level, climate, and health context [2].
A practical approach is to drink regularly across the day and adjust when you are:
- more physically active
- in hot weather
- sweating more than usual
- running a fever
- having diarrhea or vomiting
Do not force large amounts of water just because you are fasting. More is not always better. If you have a medical condition that affects fluid needs, ask a clinician what is appropriate for you.
Common hydration mistakes while fasting
Waiting until you feel terrible to drink
Thirst is useful, but do not make it your only cue. Keep water available during the fasting window so hydration is easy.
Replacing meals with water
Water supports a fasting window, but it does not replace a meal. During your eating window, eat enough food to support your day.
Using flavored drinks that quietly add calories
Some flavored waters are no-calorie. Others contain sugar or other calorie sources. Check the label if your fasting goal depends on keeping the window calorie-free.
Ignoring symptoms
Side effects with intermittent fasting can include tiredness, dizziness, headaches, mood changes, and constipation [3]. If symptoms keep happening, adjust the fasting window instead of trying to push through.
How GoFasting can support your hydration routine
GoFasting can help you log fasting windows, weight, steps, calorie intake, and water intake, then review patterns as you adjust your routine.
Use tracking as feedback, not judgment. Logging water can make your routine easier to see, but it does not determine whether fasting is medically appropriate.
FAQ
Does water break intermittent fasting?
Plain water does not break a calorie-free fasting window.
Can I drink lemon water while fasting?
A small squeeze of lemon in water is often considered a low-calorie choice, but strict fasting styles may avoid it. If you want the simplest fasting window, choose plain water.
Is sparkling water okay during intermittent fasting?
Plain sparkling water with no sugar and no calories can fit many fasting routines. Check the label if it is flavored.
Can I drink electrolyte water while fasting?
It depends on what is in it. Some electrolyte drinks contain sugar or calories. If you have medical needs, heavy sweating, or symptoms, ask a clinician instead of guessing with supplements.
Should I do intermittent fasting without water?
No. Dry fasting is not a good default. Intermittent fasting does not require avoiding water, and dehydration can create health problems.
Bottom line
Water is allowed during intermittent fasting, and plain water is the easiest choice. Keep the fasting window simple, avoid calorie-containing drinks, and pay attention to symptoms. A fasting routine should feel repeatable, not like a dehydration test.
Medical disclaimer
This article is for general educational purposes only and is not medical advice. Talk with a qualified healthcare professional before changing your eating or drinking routine if you have a medical condition or develop concerning symptoms.
References
- Johns Hopkins Medicine. Intermittent Fasting: What Is It, And How Does It Work? https://www.hopkinsmedicine.org/health/expert-qa/intermittent-fasting-what-is-it-and-how-does-it-work
- CDC. About Water and Healthier Drinks https://www.cdc.gov/healthy-weight-growth/water-healthy-drinks/index.html
- Mayo Clinic. Intermittent fasting: What are the benefits? https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/intermittent-fasting/faq-20441303