Is Carbonated Water Bad for You? 8 Side Effects of Drinking It

Carbonated water seems as benign as the bubbles rising in the glass—but is it?

For perspective, consider the apple: An apple appears healthy, too. "An apple a day keeps the doctor away," so the saying goes. But bake it into a buttery crisp or pie adorned with scoops of ice cream, toffee chunks and a caramel drizzle, and you've suddenly turned that sinless apple into a sugary saturated fat dessert from hell.

Likewise, not all carbonated water concoctions are healthy. Soda is carbonated water after all, but adulterated with high-fructose corn syrup, brominated vegetable oil, often caffeine, and either caramel coloring or, in the case of orange soda, yellow 6 and red 40.

OK, that's an extreme example. While far less bastardized than cola, sparkling waters flavored with fruit essence, too, may not be the ideal beverage for a health-conscious person like you. And that begs the question…

What the heck is carbonated water, anyway?

In short, carbonated water is simply bubbly water. Technically, it's H2O infused with CO2, the same carbon dioxide you exhale.

The book Trends in Non-alcoholic Beverages, 2020 explains it simply as the dissolution of cold CO2 gas in water under high pressure. These bubble dynamics turn plain water into fizzy water, also known as carbonated water, soda water, seltzer, club soda, etc. When the gas dissolves in water naturally underground in wells and springs, it's called sparkling water, and it contains minerals like sodium and calcium. (Think: Perrier mineral water or San Pellegrino.)

Otherwise, CO2 is pumped in through an industrial process at a beverage plant or by the soda maker device on your bar or kitchen counter. Add sugar, coloring and other stuff and you get Coca-Cola and its cousins. Tonic water is another type of carbonated water, but with bitter quinine and high-fructose corn syrup added, which makes your double shot gin & tonic about 150 calories.

Consumer desire to avoid those sugary, high-calorie sodas has made seltzers and sparkling waters all the rage, say dietitians we spoke with. The market for these seemingly healthier bottled beverages is expected to grow to $93.6 billion by 2033, according to Future Market Insights. Considering America's obesity crisis and the number of diabetics topping 37 million (97 million adults have prediabetes, according to the American Diabetes Association), most experts welcome that trends.

8 Side Effects of Drinking Carbonated Water

Club soda sparkling water — Shutterstock

1. You'll improve hydration

"Pure, plain carbonated water is still water and can help you stay hydrated, especially if you struggle to drink enough plain water throughout the day," says Lauren Manaker, MS, RDN, author of The First Time Mom's Pregnancy Cookbook and Fueling Male Fertility.

"There's no scientific evidence to suggest that carbonated water is bad for you," says registered dietitian Mary Wirtz, MS, RDN, CSSD, a board-certified sports dietitian, and consultant for Mom Loves Best. "I support individuals drinking carbonated water to increase baseline hydration. Most women should consume 11.5 cups of hydrating beverages daily, while men should aim for 15.5 cups, according to the National Academies of Sciences, Engineering, and Medicine. This can be daunting, but carbonated water, among other beverages, can make this goal more achievable."

2. You may enjoy drinking water more

The fizz of carbonated water makes it seem more enjoyable than drinking plain water. Added flavors do the same. "

They won't bore you," says Katherine Gomez, RD, a registered dietitian with clinical and research experience who is also a medical reviewer for PsycheMag. "Carbonated waters come in a variety of highly satisfying flavors, and we often feel like having more and more."

Of course, you can always squeeze a lemon into plain carbonated water or add fresh or frozen fruit slices for flavor.

3. It may bloat your belly

When you drink carbonated water, you swallow more air than you normally would by eating or drinking anything else due to the CO2 trapped in the water.

"Those bubbles may cause bloating, which can be uncomfortable," says Manaker. "This can especially be troublesome for people suffering with irritable bowel syndrome (IBS)."

The fizzy stimulation in the gut can cause constipation or trigger loose bowel movements. On the flip side, the bubbly expansion in your stomach may result in calorie-free satiety. One study compared the effect of carbonated water to the influence of still water on feelings of hunger and satiety in a small group of young women. Researchers found that greater fullness and decreased feelings of hunger occurred only when the women consumed the carbonated water.

4. You might gain weight

Bloated woman putting on jeans — Shutterstock

A few studies suggest that carbonated water—with or without artificial sweeteners—may lead to weight gain and a greater body mass index even though they may contain zero calories. How so?

For one, "artificial sweeteners can have negative effects on digestive health and blood sugar levels as well as serious health side effects," notes registered dietitian nutritionist Mary Sabat, MS, RDN, owner of Body Design by Mary.

For example, research published in 2014 in Nature demonstrated that nonnutritive sweeteners changed the intestinal microbiome of both mice and humans, and can negatively impact metabolism and glucose response. And a meta-analysis of observational studies published in the Canadian Medical Association Journal linked nonnutritive sweeteners to increases in weight and waist circumference, and higher incidence of obesity, hypertension, metabolic syndrome, type 2 diabetes, and cardiovascular events.

But even those innocent bubbles in pure unadulterated sparkling water may play a role in weight gain. Small experiments on rats and humans published in 2017 in Obesity Research and Clinical Practice suggest that the fizziness caused by the carbon dioxide in beverages causes the release of the so-called hunger hormone ghrelin, which may prompt overeating.

5. You may lose weight

Zero-calorie diet soda is essentially carbonated water with coloring and an artificial sweetener added. It's used by millions of dieters in place of sugar-sweetened beverages for decades and some studies have shown their efficacy in reducing bodyweight. While there's little research on pure sparkling water, zero-calorie carbonated water without coloring and artificial sweeteners added may work the same way as artificially sweetened no- and low-cal drinks.

"As a replacement for sugary drinks, carbonated water can help reduce your calorie intake and support your weight-loss efforts," says registered dietitian Barbara Kovalenko, RD, and nutrition consultant at the weight-loss app Lasta.

6. It may erode your teeth

Not to the extent that drinking lots of soda will, but, yes, unsweetened carbonated water can contribute to cavities.

"Carbonated water may have a lower pH than regular still water, and that lower pH can erode tooth enamel over time," says Manaker.

Acidic drinks like fruit juice, sugary sodas and even sparkling waters, especially those that are citrus-flavored, can dissolve the minerals in our teeth, according to a study published recently in the Journal of the American Dental Association (JADA). Related research in JADA Foundational Science found that the dentin, the area under the enamel that protects the nerves, is particularly susceptible to erosion from sugar-free carbonated waters.

7. It may make you more alert

When the summer sun is beating down and you're sweating, a drink of either plain water or carbonated water will rehydrate you. But if you want to stay alert and avoid heat-related drowsiness, go for the bubbly stuff. In a 2022 experiment reported in the journal Physiological Behavior, researchers gave healthy young adults either cold carbonated or cold non-carbonated water in a stressfully hot environment. Their analysis found that the carbonated water caused an increase in cerebral blood flow and blood pressure and greater feelings of motivation and exhilaration compared with the plain water.

8. Some may cause health problems

Some seltzers and carbonated waters contain potentially unhealthy levels of synthetic PFAS chemicals that have been linked to a variety of health issues, according to a study by Consumer Reports in 2020.

"Many popular beverage brands contain these chemicals known as per- and polyfluoroakyl substances (PFAS)," says Trista Best, MPH, RD, LD, a registered dietitian for Balance Once Supplements. "These man-made chemicals often used in food packaging are also known as "forever chemicals" because they are difficult to break down in the body or the environment."

Epidemiological studies suggest potential associations between PFAS exposure and liver disease, altered, immune and thyroid function, insulin dysregulation, kidney disease and some cancers. The Environmental Protection Agency recommends limiting PFASs in bottled water to 70 parts per trillion (ppt), but each state can set their own standards with some as low as 12 ppt. Some experts call for less than 1 ppt to be acceptable.

So, is carbonated water actually bad for you? The verdict

Class of Seltzer with Lime — Shutterstock

There's very little evidence to suggest that drinking carbonated water poses a risk to your health.

"Generally speaking, it's not bad for you and it may actually provide some potential health benefits," says Sabat. "Carbonated water can help to keep you hydrated, as it has the same amount of electrolytes as regular water."

While it may cause bloating, some people find it relieves indigestion and reduces gas discomfort. Drinking carbonated water may keep you from overeating (and help you lose weight) thanks to the satiating bubbles and water volume as long as your beverage doesn't contain 12 teaspoons of sugar like most carbonated sodas do. And those citrus-flavored seltzers—even the sparkling water you squeeze lemons, limes and oranges into to add flavor—are unlikely to rot your teeth unless you drink a lot of them every day. Even then, you can reduce the risk simply by rinsing your mouth with water after downing a glass to neutralize the acids.

The bottom line: "Carbonated beverages can serve a great purpose in your health, but the kind you choose should be considered carefully," says Best.

And when in doubt, you can't go wrong choosing that sports drink of your childhood—cold, refreshing water from the garden hose.

What the heck is carbonated water, anyway?