Is diet tonic water good for you?

What is diet tonic water?

Diet tonic water is a variation of regular tonic water that contains artificial sweeteners instead of sugar. Like regular tonic water, diet tonic water contains quinine, which gives it a bitter taste and can act as a mild muscle relaxant. The main differences between regular and diet tonic water are the sweeteners used and the calorie content.

Sweeteners in diet tonic water

The most common sweeteners used in diet tonic water are:

  • Aspartame
  • Acesulfame potassium (Ace-K)
  • Sucralose
  • Saccharin

These artificial sweeteners provide the sweet taste of regular tonic water without all the calories. They allow people to enjoy the flavor of tonic water without worrying about sugar and carb intake.

Calories in diet vs. regular tonic water

A 12-ounce serving of regular tonic water contains about 130 calories, all from sugar.

Diet tonic water contains 0-2 calories per serving. This calorie reduction is possible because artificial sweeteners are used instead of sugar.

So diet tonic water is an essentially zero calorie alternative to enjoy the flavor of quinine and carbonation without the high calorie content.

Is it healthy to drink diet tonic water?

Diet tonic water contains no nutrients itself, so the healthiness depends entirely on how it affects you. Here are some of the key considerations:


  • Zero calories help with weight control or maintenance
  • Allows enjoyment of tonic flavor without sugar/carb intake
  • Quinine content may have mild medicinal effects

The lack of calories and sugar makes diet tonic water a better choice than regular tonic for people monitoring carbohydrate intake and trying to manage weight. Enjoying the carbonation and bitter quinine flavor without calories can help with goals around blood sugar and body weight.

The quinine content also has some potential health benefits. It acts as a very mild muscle relaxant, which has made tonic water a popular drink complementing gin or vodka and providing a slight therapeutic effect.


  • Artificial sweeteners may negatively impact gut bacteria
  • Carbonation can cause digestive issues for some people
  • No nutrients aside from trace quinine content

While diet drinks help many people reduce calorie intake, there are some drawbacks. Artificial sweeteners may negatively impact the balance of bacteria in your digestive system. For people who are sensitive to it, carbonation can also cause digestive upset like bloating or reflux. Lastly, since diet tonic water has no nutrients, it doesn’t offer health benefits aside from light pain/muscle relaxing properties from the quinine.

Consider your personal tolerances

The impact of diet tonic water will depend on the individual. People vary greatly in how their bodies handle artificial sweeteners and carbonation. Check with your doctor if you have concerns about how diet drinks may affect your gut health or digestive issues. Otherwise, enjoy diet tonic water in moderation as a low-calorie drink option.

Diet tonic water benefits

Here is a summary of the most important benefits of drinking diet tonic water:

Low in calories

With 0-2 calories per serving, diet tonic water is essentially zero calorie. This makes it a great option if you are counting calories or managing blood sugar levels. The lack of sugar means it won’t spike blood glucose like regular soda and tonic.

Enjoy flavor without calories

Many people find they miss the carbonation and unique flavor of tonic water when they eliminate sugary drinks. Diet tonic allows you to enjoy these tonic properties without unwanted calories influencing weight and diabetes risk.

Mild muscle relaxing effect

The quinine in tonic water has a mild therapeutic effect on skeletal muscle. It can help relax clenched muscles and cramping. This makes it a nice complement to alcoholic drinks, enhancing the relaxing effect. It may also help with restless legs syndrome.

Alternative to water

Diet tonic provides flavor and carbonation, making it a more interesting drink choice than plain water. For those who get bored with water, it can help increase overall fluids.

Suppresses appetite mildly

Research shows carbonated drinks can slightly reduce appetite and food intake. The combination of bubbles and bitter quinine appear to have an appetite suppressing effect for some people.

Diet tonic water drawbacks

Here are some of the downsides associated with regularly drinking diet tonic water:

Artificial sweeteners may harm gut bacteria

There is some evidence that artificial sweeteners like aspartame and saccharin negatively impact the balance of bacteria in your digestive system. They may feed harmful bacteria while starving beneficial bacteria.

Carbonation causes digestive distress

The bubbles in carbonated drinks may increase acid reflux symptoms or contribute to bloating and gas for sensitive individuals. People prone to heartburn or irritable bowel syndrome (IBS) often find carbonated drinks make symptoms worse.

No nutritional value

Aside from trace amounts of quinine, diet tonic water provides no vitamins, minerals, antioxidants or other nutrients. It essentially contains only carbonated water and artificial sweeteners. It does not contribute any real nutrition to your diet.

Linked to increased food cravings

There is some evidence diet soda triggers reward and craving sensors in the brain, increasing your motivation and temptation to indulge in sugary and processed junk foods. This may undermine weight management.

Associated with weight gain

Some large cohort studies have linked consumption of diet drinks to increased risk for obesity and metabolic disease over time. More research is needed to confirm cause vs correlation.

Is diet tonic water Keto friendly?

Diet tonic water is generally considered Keto friendly, since it’s very low in carbohydrates and will not take you out of ketosis. A 12 oz serving contains less than 1g carb.

However, there are a few cautions for keto dieters considering diet tonic water:

  • May trigger cravings for sweets or carb foods
  • Artificial sweeteners may disrupt gut health
  • Carbonation can cause digestive issues

While it won’t impact ketosis, the taste of sweetness may activate cravings and hunger. Artificial sweeteners and carbonation may also influence gut issues and digestion in ways counterproductive to keto’s goals of blood sugar control and weight loss.

Overall it’s a grey area, unlikely to throw you off track too badly, but possibly not the best choice compared to unsweetened carbonated waters that provide bubbles without sweet taste.

Does diet tonic water break a fast?

During fasting, the key is avoiding calories to sustain the fasted state. Since diet tonic water generally has 0-2 calories per serving, it will not break your fast thermogenically. However, even no/low calorie sweeteners may trigger an insulin response in some individuals, taking you out of the fasted state on a metabolic level.

Given this, most experts advise against diet drinks during fasting windows, recommending unsweetened teas, black coffee or plain water instead. The sweet taste and insulin triggering effect of artificial sweeteners make diet soda and tonic suboptimal choices when fasting. They may undermine some of the hormonal benefits.

Diet tonic water and weight loss

Replacing high calorie regular tonic water with zero calorie diet tonic water should help with weight loss and control by reducing liquid calorie intake.

However, research on diet sodas casts doubt on whether artificially sweetened drinks truly help weight management for everyone. Some studies link diet soda to increased obesity risk.

Potential reasons diet drinks may undermine weight loss:

  • Confuse the body with disconnect between sweet taste and calories
  • Increase cravings for sugary foods
  • Disrupt appetite signals and satiety

Diet tonic water gives you taste without energy, which may misalign biological hunger/fullness regulators. The brain tastes sweetness and prepares for calories that never arrive.

Overall, diet tonic water is likely better for weight loss than regular tonic due to the calorie reduction. But for optimal progress, unsweetened options like plain or lime sparkling water may be preferable.

Is diet tonic water bad for your teeth?

Diet tonic water has minimal direct impact on tooth health, since it does not contain sugar. The primary dental concern with drinks is that sugar provides “food” for the plaque bacteria that create acids eroding tooth enamel.

However, the acids in any carbonated drink may have subtle damaging effects on enamel over time. And the phosphoric acid added to enhance tartness can potentially damage enamel. But since it does not contain sugar, the impact of diet tonic water on teeth is generally neutral to mildly negative.

The greater risk for teeth comes from using it as a mixer for alcoholic drinks. Alcohol is drying and sugary mixers like juice or regular tonic amplify damage. Overall, diet tonic water is not especially bad for your teeth on its own. Just limit acidic exposure and practice good dental hygiene.

Diet tonic water nutritional info

Here is the basic nutrition information for a 12 ounce serving of diet tonic water:

Calories 0-2 calories
Total fat 0 g
Sodium 15-40 mg
Total carbs 0-1 g
Sugars 0 g
Protein 0 g

As you can see, there are minimal calories, carbs, and no fat or protein. The only mineral present in small amounts is sodium from added salt/preservatives.

There are also trace amounts of vitamins and quinine, but not enough to significantly contribute. Overall, diet tonic water provides flavor and sensation without any notable nutrition.

Alternatives to diet tonic water

If you are looking to avoid artificial sweeteners but like the flavor of diet tonic, here are some alternatives to consider:

Unsweetened seltzer or sparkling water

These provide the carbonation without any sweeteners. You can add your own lime, lemon, or other fruit flavors. The hint of bitterness from carbonating pure water mimics tonic taste.

Diluted tonic syrup

Tonic syrup consists of concentrated quinine and sugar without added water. You can dilute small amounts of tonic syrup with seltzer or soda water to control sweetness.

Stevia-sweetened tonic water

Some niche brands now make tonic water sweetened with stevia instead of artificial sweeteners. Stevia is natural and generally well tolerated.

Fruit-infused waters

For some, the appeal of tonic water is having a flavored, more interesting drink than plain water. You can infuse water with fruits like berries, citrus, cucumber to provide light flavor.

The bottom line

Diet tonic water won’t provide any significant nutrition, but it can be an enjoyable low-calorie drink in moderation. The risks from artificial sweeteners appear quite small at typical intake levels. Just be mindful that for some, carbonation and sweeteners may cause digestive or craving issues.

While fine in small amounts, you’ll maximize potential benefits by focusing on unsweetened waters, teas, black coffee to meet your hydration needs. Use diet tonic as an occasional treat rather than a daily drink. And as always, aim for variety and balance in your diet.

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