Carbonated beverages are made for drinking — but they're also famous for their sound: the "pop!" of a champagne bottle, the "crack" of a soda can, the "fizz" of a crisp, cool glass of sparkling water. "Sounds" fabulous, sure, but sometimes these drinks can make you feel sick.
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Read more: Is Carbonated Water Bad for You?
What makes soda, beer and other fizzy drinks different from flat beverages has to do with gas. "Carbonation, which adds a unique flavor and texture to beverages, is the process of trapping and dissolving the gas CO2 [carbon dioxide] in water," says Amanda Blake, RDN, a nutritionist with Pacific Nutrition Partners in Los Angeles.
If you took physics, you learned that gas and liquid are two different states of matter — meaning they won't blend together, and bubbles of the gas rise to the top of the glass. Upon drinking a carbonated beverage, your tongue catches the carbonation first, as the bubbles pop in your mouth. But after the drink is swallowed, the carbonation might have a negative effect on your stomach.
Feeling Sick From Carbonation
Think of swallowing a fizzy drink like swallowing a big gulp of only air —they're more similar than you might think.
"Swallowing a carbonated beverage introduces air into the stomach, similar to eating too fast or drinking too rapidly," says Blake, and this can translate to stomach pain after drinking carbonated beverages.
A small study, published in the Journal of Nutrition in December 2018, tested the effects of carbonated beverages on 34 people (half women and half men) and found that carbon dioxide increases what's known as gastric volume, which can lead to discomfort — feelings of bloating, nausea or fullness, for instance.
But, according to Blake, gas already plays a part in the digestion of food so, for some people, there are no side effects of drinking carbonated beverages.
"Individuals may react differently to carbonation," she says. "Some may feel bloated and distended, others may not notice any difference or [may] release excess gas in the form of a harmless belch. Some may experience a feeling of fullness with a carbonated beverage, while it may drive the hunger of others."
Another small study, this one published in PLoS One in September 2016, found that carbonated drinks like seltzers, sodas, beer and sparkling water make people feel as if they've had more to drink than they actually have, due in part to what's described as gastric filling — in this case, filling up the stomach with air from the bubbles. The researchers also noted that pain receptors in the body may detect cold and carbonation and register them as pain.
Read more: The 9 Worst Foods for Bloating
Who Should Avoid Fizzy Drinks
Although studies have not linked carbonated beverages to chronic health issues like irritable bowel syndrome (IBS) or gastroesophageal reflux disease (GERD), those living with these and other conditions may find fizzy drinks make their symptoms worse and cause more pain.
"The acidity level and carbonation may aggravate symptoms for some," says Cassie Berger, RDN, who also is a nutritionist with Pacific Nutrition Partners. "It's best for individuals to assess their own tolerance levels and modify intake if needed." She recommends diluting a fizzy drink with juice or coconut water to lessen the nausea effect.
"The bottom line," Blake adds, "is avoid carbonation if it causes you discomfort."
- PLoS One: “Oral Cooling and Carbonation Increase the Perception of Drinking and Thirst Quenching in Thirsty Adults”
- Journal of Nutrition: “Men and Women Differ in Gastric Fluid Retention and Neural Activation after Consumption of Carbonated Beverages”
- Amanda Blake, RDN, Pacific Nutrition Partners, Los Angeles
- Cassie Berger, RDN, nutritionist, Pacific Nutrition Partners, Los Angeles