Drinking fizzy water may be able to help dieters lose some weight, researchers said on Tuesday.
Because the drink is "filling" and helps to curb hunger pangs, it has been heralded as a potential slimming aid. It may also speed up digestion and lowers blood glucose levels, analysis published in BMJ Nutrition Prevention & Health found, although how it works is not fully understood and author Akira Takahashi also warned fizzy water cannot be relied on alone.
Carbon dioxide (CO2) in fizzy water is absorbed through the stomach lining and is rapidly converted to bicarbonate (HCO3) in red blood cells, Mr Takahashi said. An alkalinisation process then speeds up glucose absorption by activating key enzymes in red blood cells, the author said.
Clinical observations showed that blood glucose levels fall as blood passes through a dialyser, despite a higher glucose level in the dialysate solution to start with, he added.
While these findings suggest that fizzy water may indirectly promote weight loss by enhancing the uptake and use of blood glucose, context is key, Mr Takahashi said.
During a typical four-hour haemodialysis session, about 48,000ml of blood flows through the dialyser, resulting in around 9.5g of glucose being used during the session, he said.
“Given this minimal glucose reduction, the impact of CO2 in carbonated water is not a stand-alone solution for weight loss. A balanced diet and regular physical activity remain crucial components of sustainable weight management,” he added.
Prof Sumantra Ray, executive director at NNEdPro Global Institute for Food, Nutrition and Health, which co-owns the journal, said: “While there is a hypothetical link between carbonated water and glucose metabolism, this has yet to be tested in well-designed human intervention studies.
“And although this study adds to the evidence base, it doesn’t provide sufficient evidence on which to make recommendations for the preventive or therapeutic use of carbonated water.”
