Does drinking water break a fast?

No. Water has zero calories and keeps every kind of fast, from 16:8 to a multi-day water fast.

Can I drink flavored water while fasting?

Only if it has no calories and no sugar. Water with a slice of lemon or a few mint leaves is fine; sweetened enhanced waters are not.

How much water should I drink while fasting?

About as much as on a normal day, plus a little extra because you are not getting water from food. Let thirst and pale urine guide you.

Can drinking water stop hunger during a fast?

It can help for a while, since a fuller stomach sends short-term fullness signals. Hunger usually comes in waves and passes on its own too.

Does Water Break a Fast? No

Reviewed by the FastTrack team · Updated June 2026

Short answer: No

Water does not break a fast. Plain still, sparkling or mineral water has zero calories and is the one drink every type of fast allows, including a strict water fast. Drinking enough of it is part of fasting safely.

Calories	0 kcal
Breaks a weight-loss fast?	No
Breaks ketosis?	No
Breaks autophagy?	No
Insulin impact	None

Why water is the base of every fast

A fast means going without energy, and fluids are always allowed. Water has no calories, carbohydrate or protein, so it cannot raise insulin or interrupt ketosis or autophagy. You also lose water faster while fasting, because the glycogen stored in your liver and muscles holds water and gets used up during the first day.

When water stops being plain

Flavor drops, syrups and enhanced waters can hide sugar, so check the label for calories. A slice of lemon or cucumber is fine. Very large amounts in a short time can dilute blood sodium: sip through the day instead of forcing liters at once, and add a pinch of salt or an electrolyte drink on long fasts.

How much is safe

Aim for about the same fluids you drink on a normal day, plus extra in heat or after exercise, since food usually supplies part of your water. Pale yellow urine is a simple check.

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Frequently asked questions

Does drinking water break a fast?: No. Water has zero calories and keeps every kind of fast, from 16:8 to a multi-day water fast.
Can I drink flavored water while fasting?: Only if it has no calories and no sugar. Water with a slice of lemon or a few mint leaves is fine; sweetened enhanced waters are not.
How much water should I drink while fasting?: About as much as on a normal day, plus a little extra because you are not getting water from food. Let thirst and pale urine guide you.
Can drinking water stop hunger during a fast?: It can help for a while, since a fuller stomach sends short-term fullness signals. Hunger usually comes in waves and passes on its own too.