Does Sparkling Water Break a Fast?

Hand holding a can of LaCroix sparkling water

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If you find yourself unsure of what beverages are okay to consume while fasting, you’re not alone. People commonly ask if you can drink sparkling water while intermittent fasting. Will sparkling water raise your blood sugar, spike your insulin, and break your fast?

The answer is simpler than you might think: Foods that contain no calories will not break a fast. Sparkling water typically meets that standard since most brands contain zero calories, even when flavored. However, check the label to be sure. A few brands contain small amounts of sugar, and some may contain artificial sweeteners.

If you are concerned with the carbonation in sparkling water causing your blood sugar to spike, there’s no need for worry. The carbonation in unsweetened sparkling water like LaCroix, Bubly, or Topo Chico will not impact your blood sugar.

Note: Fasting can be dangerous if performed without care. Consult with a medical professional before fasting or making significant changes to your diet, especially if you have an existing medical condition. Failure to heed professional medical advice many result in injury, illness, or even death.

Man drinking sparkling water by a shore

Drinking Flavored Sparkling Water During a Fast

Fasting can be tough, and plain water gets old fast. If you’re considering a can of LaCroix but not sure how it might impact your fast, relax — you’re in the clear. Flavored sparkling water will not break a fast, so long as it does not contain sugar.

Most popular brands of flavored sparkling water like LaCroix, Polar Seltzer, and Topo Chico do not contain sugar. LaCroix’s flavored sparkling waters are flavored using “natural essence oils” extracted from real fruit. This flavoring method seems to be common among a variety of brands of sparkling water.

Sparkling water adheres to a variety of popular modern diets — including the paleo and ketogenic diets.

However, a few brands of sparkling water do contain small amounts of sugar. For example, Spindrift sparkling water contains real fruit juice for big flavor. The various flavors contain between 9 and 15 calories per can. These calories are the result of 1-3 grams of sugar, depending on the flavor. While the amount of sugar is quite small, sparkling water brands like Spindrift will technically break your fast.

LaCroix nutrition facts

Sparkling Water with Artificial Sweeteners

You might not think of artificially sweetened beverages as true sparkling water, but technically, the United States Food and Drug Administration allows them to be labeled as such. Sparkling Ice, for example, is a brand of sparkling water that contains artificial sweeteners.

While artificial sweeteners are unlikely to break your fast, scientists are divided over whether they are healthy to consume, and in what quantities. Studies have resulted in conclusions ranging from artificial sweeteners being “safe under all conditions” to “unsafe at any dose.”

If you’re looking for a flavored sparkling water that contains no artificial sweeteners, there are plenty of great options. In fact, most sparkling water brands are sweetener free. These include popular brands such as:

  • LaCroix
  • Bubly
  • Topo Chico
  • Polar Seltzer

Another great way to maintain control over the additives in your sparkling water is to make your own carbonated water at home. There are a variety of affordable and reliable home sparkling water machines that can make fasting easier and more enjoyable.

If you’re new to homemade sparkling water, start with SodaStream. Their designs are simple and reliable, and the gas canisters are widely available. You can even add natural sweeteners like stevia if you prefer a bit of sweetness, while avoiding artificiality.

Water Enhancers and Flavor Drops

If you make your own sparkling water at home, water enhancers and flavor drops can be a great way to add a bit of flavor. Fortunately, you can find water enhancers that contain zero calories. That means they should be suitable for intermittent fasting.

However, be sure to check your flavor drops for other ingredients such as artificial sweeteners. While they are calorie free and unlikely to spike your insulin, many people choose to avoid them while fasting.

Caffeinated Sparkling Water

Caffeinated sparkling water is an excellent choice while fasting. It provides the caffeine kick that many of us rely on, without the calories of a coffee with cream and sugar (note that black coffee is fine to drink while fasting).

Brands like Hiball sparkling energy water contain zero sugar, zero calories and no sweeteners of any kind. Naturally flavored, they essentially taste like LaCroix, but with a strong dose of caffeine added.

Sparkling Mineral Water

Mineral water is another great choice for intermittent fasting. It’s close to the same as sparkling water, but it comes from a natural source and contains a significant dose of minerals. In addition to keeping you hydrated, it offers minerals like calcium, magnesium, and potassium. These minerals are inherently calorie free and can play a helpful role in lowering blood pressure, strengthening bones, and improving circulation. They can also be helpful for replenishing lost nutrients after a vigorous workout.

Other Beverages That Won’t Break a Fast

You might be curious about what all you can drink while fasting. While the below list is not exhaustive, it’s a great starting place if you’re looking for no-calorie drinks to enjoy while fasting.

  • Sparkling water
  • Mineral water
  • Black coffee
  • Tea (with no honey, milk or other additives)
  • Mint or cucumber infused water

Sparkling Water Before Blood Work

Intermittent fasting is not the same as fasting before blood work, and different rules apply.

If you are preparing to provide a blood sample for a laboratory test ordered by your medical provider, you may be asked to fast. Your medical provider should be able to provide detailed instructions regarding what is okay to consume. Always heed their advice.

However, general guidelines for fasting before blood work are:

  • Do not eat anything for 8-12 hours before the test
  • It is okay to drink plain, flat water

You should avoid drinking carbonated or flavored water before blood work. The dissolved carbon dioxide (CO2) in sparkling water can have an impact on your blood chemistry. That means LaCroix and other flavored sparkling waters are not permitted, unless your provider explicitly tells you otherwise.

Is Sparkling Water Okay for Fasting?

The final verdict is that yes — most sparkling water is perfectly fine to drink while intermittent fasting — even flavored sparkling water. However, be sure to check the label and ensure your sparkling water is calorie free and won’t break your fast.

Also, note that there are a great variety of reasons for fasting, including weight loss, religious and medical purposes. Not all of the same rules apply in each situation. Consult with the appropriate medical, religious, or nutrition professional before beginning a fasting regimen.