A carbonated beverage, commonly known as soda, is a liquid infused with carbon dioxide gas under pressure, creating the familiar fizz and texture. A long-standing belief holds that allowing soda to go “flat”—removing its carbonation—makes it a healthier choice, particularly during mild illness. This notion suggests that removing the bubbles mitigates the beverage’s negative effects. To determine if flat soda offers any true health advantage, it is necessary to separate the physical effects of the gas from the liquid’s chemical composition.
The Impact of Carbonation on Digestion
The physical difference between carbonated and flat soda lies solely in the presence of dissolved carbon dioxide (\(\text{CO}_2\)). When consumed, the \(\text{CO}_2\) gas is released inside the stomach. This gas accumulation creates a mechanical effect, leading to gastric distension, fullness, and bloating.
The buildup of pressure within the stomach lining often forces a release of gas through the mouth in the form of a burp, or eructation. For individuals who have pre-existing digestive sensitivities, this gas can aggravate symptoms of conditions like irritable bowel syndrome (IBS) or gastroesophageal reflux disease (GERD). The increased pressure in the stomach may cause a temporary relaxation of the lower esophageal sphincter (LES), the muscle separating the stomach from the esophagus. When the LES relaxes, it allows stomach acid to move upward, potentially worsening the discomfort of acid reflux. Removing the carbonation eliminates this source of mechanical pressure, offering temporary relief from the associated bloating and gas.
Nutritional Components Remain Unchanged
While removing the bubbles resolves the mechanical issue of gas, it is important to recognize that the core chemical makeup of the beverage is unaffected. The nutritional profile of a flat soda is identical to its carbonated counterpart because the carbon dioxide itself contains no calories or sugar. The primary components of concern in soda—the high sugar content, caloric load, and acidity—remain fully present.
A typical 12-ounce can of regular soda contains roughly 39 grams of sugar, equating to approximately 150 calories, and this energy density is unchanged when the drink goes flat. The high acidity of soda, often due to ingredients like phosphoric acid and citric acid, is not neutralized by decarbonation. Many colas have a pH level as low as 2.5, which is highly acidic, and this level of acid persists even without the fizz.
This inherent acidity is a major factor in dental erosion, as it softens tooth enamel and creates an environment where enamel loss can occur. The removal of \(\text{CO}_2\) does nothing to mitigate the risk of tooth enamel erosion or the caloric intake. Therefore, from a nutritional and long-term health perspective, flat soda provides no significant advantage over carbonated soda; it is still a high-sugar, high-acid beverage.
Flat Soda and Stomach Upset: The Reality
Consuming flat soda, such as ginger ale or cola, as a home remedy for nausea or an upset stomach is a common cultural tradition. This habit is likely rooted in the fact that the drink is slightly hydrating, and the sugar offers quick, easily digestible energy when solid foods are difficult to tolerate. The absence of bubbles makes it less irritating than the original carbonated version, which is the sole reason for any perceived benefit.
Despite its popularity as a folk remedy, flat soda is not recommended by most medical professionals for managing gastrointestinal distress. The World Health Organization (WHO) advises against using soft drinks, even flat ones, for rehydration because they contain inadequate amounts of essential electrolytes like sodium and potassium. The high sugar concentration in soda can draw water into the digestive tract, potentially worsening diarrhea symptoms. For true rehydration and electrolyte replacement after vomiting or diarrhea, oral rehydration solutions are a superior choice.