Does water break a fast?
Plain water does not add calories and fits an ordinary intermittent fasting window.
By FastWindowTimer · Content updated: · Not individually medically reviewed — see editorial policy
What the answer can tell you
Each row is specific to this item. An eating-rule verdict does not establish a biological outcome.
| Goal | How to read this verdict |
|---|---|
| Weight loss / calories | Water adds no dietary energy, but drinking it does not guarantee weight loss. |
| Metabolic / insulin | Hydration is not a measurement of insulin or ketones. |
| Water-only / procedure rules | Plain water meets the water-only rule used in this comparison. |
| Autophagy: evidence limit | The cited source does not establish a dose of water that preserves human autophagy. The timer cannot measure it. |
Serving and calories
0 kcal for plain water.
What to check in practice
Water with sugar, juice or protein is not plain water. Follow separate instructions for a medical test or procedure; this page describes everyday eating schedules.
Does it depend on your fasting goal?
These verdicts describe eating rules, not a measured biological switch. Medical-test instructions and prescribed care take priority.
Compare related items
Frequently asked questions
- Can I use this answer before a blood test or procedure?
- No. Use the instructions from the service performing the test or procedure. Rules about water and timing can differ from an everyday eating window.
Sources
- Healthline — Drinking Water While Fasting: Is It Recommended? (opens in a new tab)
What this source supports: Distinguishes ordinary fasting hydration from procedure-specific rules.
What it cannot establish: No personal insulin, ketone or autophagy measurement; product-specific values must come from its label.
Source checked: