You can drink plain sparkling water while fasting, as long as it has zero calories and no sweeteners, but there are a few important caveats about flavors, hunger, and digestive comfort.

Quick Scoop

  • Plain carbonated or sparkling water (just water + CO₂, no calories) does not break most intermittent fasts or water fasts.
  • Flavored or “naturally flavored” sparkling waters may contain sweeteners or additives that can raise insulin or technically break a strict fast, so labels matter a lot.
  • Some people find bubbles help with fullness and cravings, while others feel more hunger, gas, or bloating, especially on an empty stomach.

What Counts As “Safe” Sparkling Water?

For both intermittent fasting and strict water fasts, what matters is what’s in the drink, not the bubbles themselves.

  • Generally OK while fasting
    • Plain sparkling water / seltzer: ingredients are just carbonated water, with 0 calories, 0 sugar, 0 protein, 0 fat.
* Mineral sparkling water (like Gerolsteiner-type waters people in fasting forums like) as long as it has no added sugars or sweeteners.
  • Risky or not OK during a strict fast
    • Sparkling waters with sugar or juice (even “a splash of juice”) add calories and clearly break a fast.
* Diet or flavored versions with artificial or high‑intensity sweeteners (e.g., sucralose, acesulfame K, some “natural” sweetener blends) may be fine for weight‑loss–oriented IF, but many “clean fast” approaches avoid them because of possible insulin and appetite effects.

* Sparkling drinks with added amino acids, collagen, MCT, or vitamins with calories will break a fast under almost any definition.

How Sparkling Water Affects Fasting

Plain sparkling water is still just water plus gas, so metabolically it behaves like regular water in most healthy people.

  • Metabolic impact
    • CO₂ has no calories, so it does not trigger a measurable blood‑sugar rise by itself and does not provide energy.
* Fasting guides commonly list sparkling water alongside black coffee and unsweetened tea as “allowed” drinks that do not break the fast.
  • Digestion & gut sensations
    • Carbonation can stimulate the digestive tract and digestive enzymes, which for some people feels like better digestion; for others it can mean more rumbling or discomfort.
* Drinking a lot quickly can cause bloating, burping, or trapped gas, particularly on an empty stomach or during extended water fasts.

Hunger, Cravings, and How You Feel

Experiences here are surprisingly mixed, both in small studies and in real‑world fasting communities.

  • Can help
    • Some early data and many anecdotes suggest carbonation can create a sense of fullness and help blunt cravings, making it easier to get through tough fasting hours.
* Fasters on forums often report that “zero‑calorie sparkling water” or “wet radio static” makes the fast feel more enjoyable and keeps them away from soda.
  • Can backfire
    • Conflicting findings show carbonated water may increase ghrelin (a hunger hormone) in some individuals, potentially increasing appetite instead of reducing it.
* If you notice sparkling water makes you ravenous or very bloated, switching to still water during the fast window can feel much better.

Practical Tips While Fasting

  • Check the label carefully
    • Aim for 0 calories, 0 carbs, and no sweeteners; “carbonated water” plus minerals is usually fine.
* Be wary of “essence,” “natural flavor,” or “sparkling juice” lines; some include small amounts of sugar or non‑nutritive sweeteners.
  • Use it strategically
    • Sip slowly during tough hunger waves rather than chugging a large bottle at once to reduce bloating.
* Consider alternating sparkling and still water if your stomach feels gassy.
  • Match to your fasting style
    • For weight‑loss–focused intermittent fasting : plain sparkling water is widely accepted and often encouraged as a soda replacement.
* For _very strict “water only” or therapeutic fasts_ : some practitioners allow only still water; others allow plain sparkling water but forbid flavors and additives.

Online Buzz & “Trending Topic” Angle

Intermittent fasting remains very popular going into the mid‑2020s, and “can you drink sparkling water while fasting” keeps showing up in blogs, guides, and forum threads.

  • Fasting blogs and coaching sites describe sparkling water as a “fast‑friendly hydration hack” that can make adherence easier if it’s truly calorie‑free.
  • Fasting subreddits regularly host discussions where most users say zero‑calorie sparkling water is fine, with the usual caveats about sugar, sweeteners, and personal reactions.

Bottom line: If your sparkling water is just water and bubbles, no calories, and no sweeteners, it will not break most fasts and is generally considered safe—just pay attention to labels and how your own body feels.

Information gathered from public forums or data available on the internet and portrayed here.