Carbonated water may produce some weight loss but is not a ‘standalone solution’

Key takeaways:

• Carbonated water may result in weight loss by enhancing the uptake of glucose.
• It is not a standalone treatment for weight loss due to its small effects and should be consumed in moderation.

Carbonated water may indirectly produce weight loss by boosting metabolism and blood glucose uptake, according to a brief report in BMJ Nutrition, Prevention & Health.

However, its effects are so small that it should be integrated into wider weight management strategies “rather than relied on as a primary weight loss tool,” according to Akira Takahashi, MD, a doctor of medicine at Tesseikai Neurological Surgery Hospital in Japan.

Healio previously reported on an analysis that assessed the health benefits of increased water intake, one of which was varying amounts of weight loss in those with overweight or obesity.

Carbonated water “has become popular among health-conscious individuals,” leading to discussions on its possible weight loss effects resulting from it lowering blood glucose, Takahashi wrote.

“However, the specific mechanism behind the reduction in blood glucose levels is not yet fully understood.”

In the current study, Takahashi explored the relationship between carbonated water and weight change by comparing the consumption of carbonated water with hemodialysis.

The researcher explained that hemodialysis shifts blood from acidosis to alkalosis, primarily producing carbon dioxide (CO₂). This is similar to drinking carbonated water, where CO₂ is absorbed through the stomach lining and converted to bicarbonate in red blood cells, which leads to an increase in intracellular pH.

“This alkalinization accelerates glycolysis by activating key enzymes, including hexokinase and phosphofructokinase,” Takahasi explained.

He added that hemodialysis mechanisms support the idea that anaerobic glycolysis is promoted during carbonated water consumption — “enhancing the uptake of glucose from plasma into red blood cells” — as blood glucose levels during hemodialysis decrease from an average of 118.3 mg/dL before entering the dialyzer to 98.6 mg/dL after passing through, despite the glucose concentration in the dialysate being around 105 mg/dL.

However, Takahasi pointed out that about 48,000 mL of blood flows through the dialyzer during a 4-hour hemodialysis session with a blood flow rate of 200 mL a minute, which results in around 9.5 g of glucose being consumed during the session.

“Given this minimal glucose reduction, the impact of CO₂ in carbonated water is not a standalone solution for weight loss,” he said. “A balanced diet and regular physical activity remain crucial components of sustainable weight management.”

Takahashi also warned of the possible negative effects, particularly in the digestive system and in people with sensitive stomachs or pre-existing gastrointestinal issues, that could come from too much carbonated water intake.

“The primary concerns include bloating, gas and, in some cases, exacerbation of certain symptoms associated with digestive disorders,” he said. “Moderation is key to avoiding discomfort while still enjoying the possible metabolic benefits of carbonated water.”

Takashi concluded that further investigation into carbonated water is warranted “to better understand its long-term effects and optimize its role in dietary interventions.”