The combination of eating instant noodles and drinking soft drinks at the same time is not known to cause serious or life-threatening events. 

Everyone’s digestive system contains gas. We swallow air regularly, and gas can also be produced when intestinal bacteria digest some foods. Certain foods, drinks, and eating behaviors may increase the amount of gas present. 

Instant noodles typically contain a higher sodium content, which may increase thirst. Carbonated beverages contain carbon dioxide. The gas swallowed can build up and cause some pressure, which is relieved by burping or flatulence. If gas is not released by burping, it may take a longer time to pass and be accompanied by mild symptoms, like abdominal bloating and pain. The quantity of the fizzy drink matters, too. The more of it means more gas is swallowed. Eating too quickly also increases the chance of swallowing excess air and experiencing these side effects.

In 2016, misleading online reports were published about a young man from Chongqing, China who sought treatment at a local hospital for severe abdominal pain and bloating after consuming two packages of instant noodles and two bottles of cola. His portion sizes were unspecified, but his bloating was allegedly severe enough to require gastric decompression, the removal of air and other stomach contents with a tube. One article published on Sora News 24 referenced an uncited study conducted by a biology and food science professor at Chongqing Technology and Business University after hearing about this event. Results cannot be verified without the original source, but besides some belching, there is no immediate health concern related to consuming single servings of instant noodles and soda. Eating larger quantities may be associated with stomach pain.

Three years later, Atin to Video, a consumer health Facebook page, published a misleading Facebook post about a similar incident involving a man from Hangzhou. The post contains a misleading warning to avoid combining carbonated drinks and instant noodles, and has been shared over 315,000 times. It mentions an uncited research study where investigators replicated the man’s diet by combining instant noodles with a carbonated drink in a ziplock bag, and discovered that the bag “blew up” from the trapped gas that developed.

Atin to Video likened the experiment to creating a soda geyser when Mentos candies are dropped into a soda bottle. Contrary to popular belief, the soda geyser is not caused by the chemical components in Mentos candies and soda. It results from the unique physical features of Mentos candies: their weight and rough surface. Carbon dioxide from soda collects on the crevices of Mentos candies. The candies are heavy and sink to the bottom of the soda bottle, drawing the bubbles with it. The expansion of gas at the bottom of the bottle forces the liquid out, creating an “explosion.” 

Importantly, this reaction cannot be replicated in the stomach. When drinking soda, crevices throughout the mouth and throat will collect carbon dioxide bubbles before the liquid reaches the stomach. The gas will escape as a burp before the soda and Mentos mix. Similarly, the results from combining noodles and soda in a ziplock bag are both unverified and improbable. If the reported hospital visits are true, the abdominal pain and bloating these men experienced were likely caused by overeating and overdrinking carbonated beverages in a short period of time.