Is Tonic Water Keto Friendly?

keto Tonic Water

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Tonic water is a common mixer for alcoholic beverages, and I’ve had many people ask me if it is Keto friendly. It’s just as important to consider the carbs in a mixer like tonic water as it is to think about the carbs in the alcohol itself. There are a lot of options out there for tonic water, so I researched them and will give you the info you need to stay in ketosis while enjoying a cocktail.

Is tonic water keto friendly? Traditional tonic water is high in sugar, so it is not keto friendly. However, there are multiple options available on the market now in addition to a traditional tonic. You can buy diet tonic water, and it is sugar-free, has zero carbs and is keto friendly.

If you are at a bar or restaurant, knowing what questions to ask to ensure whether your tonic is safe for your keto diet is very important. When purchasing tonic water so you can make a cocktail at home, you’ll have more options. In addition to traditional tonic water, there are now premium tonic waters, and sugar-free tonic waters using both artificial and natural sweetener alternatives.

When deciding which tonic water to drink or purchase, you’re going to want to consider a number of factors. Let’s dive in and see which ones are truly keto friendly and will be the best choices for your Keto lifestyle!

What Makes Tonic Keto Friendly or Not

What’s are the ingredients in tonic water? Knowing what’s in tonic water will help you understand how to choose a tonic that is going to be keto friendly.

Tonic water is a carbonated beverage, like soda, that contains quinine and a sweetener. Sometimes referred to as Indian tonic water, it was developed by a British officer in the early 1800s as a way to combat malaria. Quinine, in large doses, can help prevent malaria but it has a very bitter flavor, so a sweetener had to be added to make it palatable.

Today’s tonic water has only a very small amount of quinine. It is regulated by the FDA, and any non-prescription product can only contain 83 parts per million. That’s about 83 mg in a liter or 20 mg in an 8 oz. glass. This is much less than the 500-1000 mg in therapeutic doses. In a small glass of tonic water, you are getting just enough quinine to taste the bitter flavor but in a safe amount.

For a keto dieter, what’s important to know is that quinine contributes zero carbs. The quinine is an alkaloid compound in the form of a salt that is dissolved in water. These salt compounds do not contribute carbs, they just add flavor.

A quick side note about quinine: there is some anecdotal evidence and “wive’s tales” about using quinine for leg cramps. Since leg cramps are sometimes experienced by new Keto dieters, some people wonder if they can drink tonic water to help alleviate the cramps.

First of all, quinine has not been approved by the FDA for use for leg cramps. In fact, in 2006, they specifically warned of the risks of such usage and are actively discouraging doctors from prescribing quinine for such. Overexposure to quinine can be hazardous to your health.

That being said, the amount of quinine in tonic water is very small and safe to drink. The amounts that pose health risks are much larger doses found in prescription-only medications.

What else is in tonic water? Take a look at these nutrition labels for two different brands of tonic. Both contain carbonated water, a sweetener (we’ll get to those details below), citric acid, quinine, and natural flavors. One also contains sodium benzoate, a preservative. With the exception of the sweeteners used, all of these ingredients are zero carb, so they do not affect ketosis.

The sweetener in the tonic water is what makes the difference when it comes to your keto diet. This is also the biggest difference between traditional, premium and sugar-free tonic waters.

Traditional Tonic Waters

Most major brands of tonic water sold in America are sweetened with high fructose corn syrup. This is a highly concentrated sugar made from corn, and while the debate may still rage about whether it is more dangerous than table sugar, for people eating a Keto diet, both are best avoided.

An 8 ounce serving of traditional tonic water is going to hit you with a whopping 24 grams of carbs. For reaching and maintaining ketosis, I suggest you keep your daily carb intake under 25 net grams. (Total carbs minus fiber equals net carbs.)

Depending on how you use tonic water as a mixer, you most likely will use between 4 and 8 ounces of tonic per cocktail. That means you may use your entire day’s allotment of carbs in one drink! While it’s technically possible to consume all your carbs in one drink and then not have any other carbs for the rest of the day, it would be difficult to do and in my opinion, not worth it.

Traditional tonic waters have way too many carbs to be keto friendly. If you are at a bar or restaurant, this is most likely what they will serve. We’ll discuss “diet tonic water” below, and (spoiler alert!) it is a better keto option. Ask your server if they have diet tonic water and can use that in your drink.

If you’re having a drink at home and buying your own tonic water, there are a lot of options out there now. Some higher-end restaurants may have other premium tonic options, too, so let’s dive into what makes them different.

Premium Tonic Waters

Premium tonic waters are very popular, with both the ingredient-conscious and high-end spirits crowds.

These more expensive tonic waters feature natural, organic, unrefined or specialty ingredients. While they may have a better flavor or mix with spirits more delicately, when it comes down to it, they still contain carbonated water, citric acid, a sweetener, and quinine.

For those of us that are watching the carb intake, that means the biggest difference comes down to the sweetener.

Natural and organic does not always mean better, especially when you’re talking about sugar. Common sweeteners in premium tonic waters include cane sugar, beet sugar, pure fructose, glucose syrup, and agave nectar.

Some of these have lower carb counts than traditional tonic waters made with high fructose corn syrup (HFCS). However, they are still high enough that drinking them will make it difficult for you to keep your daily carbs under your goal. Premium tonic waters may not contain HFCS, but that doesn’t mean they are good for your keto diet.

Take agave, for example.

Agave nectar comes from the blue agave plant, but much like HFCS, it must be highly processed to make it into the syrup that is added to products like tonic water. Also, the sugar in agave is mostly in the form of fructose. At 85% fructose, agave nectar actually has more fructose than high fructose corn syrup and more calories per tablespoon than refined white sugar!

As I said earlier, there is much debate on whether HFCS is more dangerous than refined sugar. What we do know is that fructose must be processed directly in your liver and converted to either glucose or fat. Fructose is more lipogenic (or fat producing) than glucose, and its overconsumption leads to an accumulation of fat deposits in the liver, which can lead to nonalcoholic fatty liver disease.

That doesn’t sound good to me. So if premium tonic waters have lots of sugar in them just like traditional tonic waters, what’s a keto dieter to do? Luckily, there are also sugar-free options for tonic water now!

Sugar-Free Tonic Waters and My Favorite Keto Tonic Water

Sugar-free tonic waters fall into two camps. As with all tonic waters, the difference lies in the sweetener, and sugar-free tonics can be sweetened with artificial chemical sweeteners or sweeteners that are naturally derived. All sugar-free tonic waters are zero carb, so they are all technically keto friendly.

Diet tonic waters are generally sweetened with artificial chemical sweeteners and the most common is saccharin. I avoid artificial sweeteners as much as possible, as they have a lot of potential negative side effects. At a minimum, they can disrupt your gut microbiome, with the potential to increase your risk of diabetes.

There are more natural sweetener options that are better. Stevia is a naturally sweet plant, and extracts from the stevia plant are becoming more common in products. While stevia, like any alternative sweetener, can cause side effects like digestive upset in some people, the occurrence is reported less than other sweetener alternatives.

If I am going to consume a sweetener alternative, stevia is my preference. In fact, my favorite keto friendly tonic water is sweetened with stevia.

My pick for the best keto friendly tonic water is Zevia Tonic Water Mixer. Its ingredients are carbonated water, citric acid, natural flavors, stevia leaf extract and quinine. Simple, natural and with the bitter and sweet combination of flavors that I’m looking for in a tonic water. Zevia Tonic Water is available in the health food section of my local grocery store, and it can also be easily ordered through Amazon. { See Zevia Tonic Water on Amazon >> }

Check out this chart to see how Zevia Tonic Water compares to other tonic water options.

Comparing Tonic Water Brands For The Keto Diet

I did the research on each of the most popular brands of Tonic Water and collected all of the details below.

The net carbs and calorie numbers are based upon a standard 8 ounce serving of tonic water. The last column in this table simply lets you know that if each tonic water brand is keto friendly or not.

BrandNet Carbs CaloriesSweetenerKeto?
Canada Dry Tonic Water2490HFCSno
Schweppes Tonic Water22.488HFCSno
Fever Tree Tonic Water935fructosemaybe*
Q Tonic1248agave nectarno
Fentiman’s Premium Tonic Water6325cane syrupno
Canada Dry Diet Tonic Water00saccharinyes
Zevia Tonic Mixer00steviayes

* That ‘maybe’ is a little wishy-washy, but I think it’s appropriate. In most cocktails, you’d actually be drinking closer to 4 ounces instead of the 8 ounce serving listed in the table. That means that an actual cocktail serving of Fever Tree Tonic Water would have closer to 4.5 net carbs. That would serve me in a pinch, but it wouldn’t be my first choice.

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My Favorite Way to Drink Tonic

My first experience with tonic water was actually before I discovered the Keto lifestyle. I was getting ready to go on my first ever cruise in the Carribean and I wanted to drink margaritas! I may not have been Keto, but I did eat a mostly natural diet and knew how to listen to my body.

And my body knew that margarita mix did not feel good. So I asked a friend who was a bartender what I could drink instead of margaritas that would be similar. He suggested tequila and tonic with lime.

Boy, was he right! I loved it.

I always asked for a high quality tequila, as the quality definitely made a difference in the taste of the drink. I got a few funny looks from bartenders when I first ordered my tequila and tonic cocktail, but I overheard many of those bartenders speculating as I walked away that the combination was probably pretty good.

I’m pretty sure I even saw other people trying out my new favorite cocktail before the cruise was over!

Just like a gin and tonic or a vodka and tonic, a drink doesn’t need to have a lot of ingredients to be good. When I first tried my tequila concoction, I was using traditional tonic water, with all its sugar and carbs. Now, of course, I know better. I still enjoy an occasional tequila and tonic, but now I make sure to mix with sugar-free Zevia Tonic Water Mixer.

Keto tequila for the win!

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Angela Davis

I'm Angela Davis, Co-Founder of Advantage Meals. I have a Bachelors in Anthropology and Masters in Holistic Nutrition. My passion is Ancestral Nutrition and for over a decade I've been helping Keto Diet beginners and those looking for their Primal Diet. "There is no one right way." Below are the most recent articles I've written for

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