Can You Drink LaCroix (or Other Seltzer Water) While Intermittent Fasting?

Overall, seltzer water (a.k.a. soda water, sparkling water, or carbonated water) can be a nice replacement for soda, or for diet soda.

It doesn’t have sugar like soda, or artificial sweeteners like diet soda.  It’s basically just water with bubbles, so it’s definitely a healthier choice.  

But can you drink seltzer water while fasting?

The short answer is yes. It’s okay to drink LaCroix, Bubly, or other brands of carbonated water while you fast, and you’ll still get a lot of health benefits from fasting.

On the other hand, drinking seltzer water might make it more difficult for you to fast, because it can increase hunger or cravings — at least in some people.  

Today I’ll share my own experience with seltzer water and fasting, and why I like it.  I’ll also explore the potential drawbacks of drinking seltzer water while you fast.  Then I’ll answer a few related questions.

Let’s dive right in.      

My Experience Drinking Seltzer Water While Fasting

When I first started fasting, I wasn’t in the habit of drinking soda water. So I was already pretty experienced with fasting when I started trying it.  

Since then, I’ve drunk seltzer water during both time-restricted eating (a.k.a. intermittent fasting) and extended fasting, on quite a few occasions.  I find it a pleasant distraction, whether I’m fasting at work or at home.  

I enjoy it because of the carbonation, and the slight flavor. And I haven’t really noticed any negative effects from drinking it.

(In contrast, when I drink diet soda during a fast, I tend to feel hungrier, and have lower energy levels.)

Keep in mind though-

While soda water doesn’t seem to stimulate any cravings or hunger for me, it might be an issue for someone who’s new to fasting.

If you’re somewhat of a beginner with fasting, you’ll want to be cautious with anything that could potentially derail you, including soda water.  

Why Could Seltzer Water Be a Problem During Intermittent Fasting?

Whether you’re drinking Lacroix, Bubly, or any other brand, there are a couple of reasons why seltzer water may create some issues during fasting.

1) The Flavors in Seltzer Water Can Stimulate Cravings

Seltzer water typically includes some “natural flavors”.

The term natural flavors is kind of ambiguous, so you don’t really know exactly what’s being used.

Why does this matter?

Because those flavors may stimulate some type of cravings, and make you want to eat.  In other words, flavored soda water may make it more difficult for you to fast.  

Here’s a short interview clip discussing how natural flavors can “trick your brain” to make you eat more:

That’s one reason why some people put anything with added flavors in the category of “dirty fasting”, which they don’t recommend.

Basically, “dirty fasting” just means being a little more lenient about what you’re allowed to eat or drink, as opposed to limiting yourself to just water and salt.  

In my opinion, “dirty fasting” is fine for people who can tolerate it.  As long as you don’t go overboard with what you’re consuming, it’s still super beneficial to your health!  

But if you prefer to do more of a “clean fast” (and limit cravings), you may want to avoid anything with added flavors.    

2) Carbonated Water Stimulates Ghrelin, the “Hunger Hormone”

A 2017 study found that carbonated water increases ghrelin levels in both rats and humans.

Ghrelin is often called the “hunger hormone”, because it makes you want to eat more*.

Here’s a short animated video explaining ghrelin (and its counterpart, leptin).

The bottom line?

Any type of soda water might make you feel hungrier.

For me personally, I doubt a little ghrelin bump would be a big deal after a few days of continuous fasting, when my ketones are super high and suppressing my appetite. At that stage, it would take a lot to make me want to break my fast.

In contrast, if you don’t have that much experience with fasting, or if you’re just doing shorter daily fasts, it may not take as much to throw you off your game.  So be cautious with carbonated water while fasting. 

(*Interestingly, ghrelin levels tend to be low in the morning, which is one reason most people find it pretty easy to delay or skip breakfast.)

Related Questions

While we’re on the topic, here are a few other questions related to carbonated water and fasting.

Can You Drink Plain Soda Water While Fasting?

Plain soda water is probably a better option than flavored versions, because the flavors might cause some cravings or make you hungrier.

On the other hand, carbonation alone can stimulate hunger (by increasing the hormone called ghrelin, as mentioned above).  

So even with plain soda water, you should be cautious and pay attention to how your body reacts.

Does LaCroix (or any Flavored Sparkling Water) Spike Insulin?

To my knowledge, flavored sparkling water does not raise blood sugar or insulin levels. That’s one reason I would say you can still get a lot of health benefits from fasting, even if you drink LaCroix or other brands of sparkling water.

For example, if you have excessively high blood sugar and insulin levels (as in type 2 diabetes, or prediabetes), you can still lower them by fasting — even if you drink tons of seltzer water!

On the other hand, seltzer water may have some small indirect effect on your blood sugar and insulin levels, through its effects on ghrelin, or perhaps via the taste receptors in your gut.

More research is needed, but in the meantime pay close attention to your individual response, and consider keeping a journal about how you react to different substances.   

How is Soda Water Different From Diet Soda?

Both soda water and diet soda have zero calories.  And they’re both carbonated.  

The major difference is that soda water doesn’t have any of the artificial sweeteners you’d normally find in diet soda, such as aspartame or sucralose.

Artificial sweeteners are associated with various health problems, and tend to stimulate cravings and make people feel hungrier. So it’s typically better to avoid them, whether you’re fasting or not.  

(There’s also a newer brand of diet soda called “Zevia” that’s made with stevia, a natural sweetener.  While Zevia is probably a healthier choice than traditional diet soda, it’s still more likely to spur cravings compared with unsweetened seltzer water.)

Can You Drink Perrier While Fasting?

Perrier is just another brand of sparkling water, which calls itself “carbonated mineral water” because it contains a bit of calcium and sodium.    

In the end, Perrier is not that much different from LaCroix, so the answer is still the same:

It’s usually fine to drink Perrier while you’re fasting, but be cautious and pay attention to your individual response.  It could cause cravings or make you feel hungrier.

(The same answer would apply to similar “high end” brands of sparkling water, like Pellegrino or Topo Chico.)

Can You Drink Flavored Water While Intermittent Fasting?

As long as it doesn’t have any sugar or sweeteners, it’s okay to use flavored water while you fast.

If it does have sweeteners, it may still be okay to use, but I wouldn’t really recommend it.  Even moreso than natural flavors alone, sweeteners tend to cause cravings and other challenges while fasting.

Always pay attention to your individual response, so you can identify any substances that make fasting more difficult for you, and avoid them in the future. 

The Bottom Line: Should You Drink LaCroix While Intermittent Fasting?

Lacroix, Bubbly, or any other type of sparkling water are all pretty reasonable things to drink while you fast, with a couple big caveats:

First, the natural flavors might cause cravings and make you want to eat more.

Second, carbonation stimulates a hormone called ghrelin, which can make you hungrier.

It’s probably a good idea to keep a journal, and see how different substances affect you. For example, you may notice that you always get a little bit hungrier after you drink soda water. If that’s the case, obviously you should avoid it while fasting. 

If you can tolerate it, drinking seltzer water while fasting is not a big problem, and you’ll still get a lot of health benefits.

Overall, you’re much better off fasting with seltzer water than not fasting at all!

I hope you found this article helpful. 🙂

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