Can Sparkling Water Aid Weight Loss? Researchers and Dieticians Are Still Split

Sparkling water can boost a person’s metabolism, contributing to weight loss, according to a new paper published in BMJ Nutrition, Prevention & Health.

This contribution, however, is minor and, according to some dieticians, may be negligible. 

Still or startling?

Drinking carbonated water has become an online health trend in recent years to aid weight loss.

To determine whether the tactic really provides any benefit, one researcher from Tesseikai Neurosurgery Hospital, Japan, decided to reassess a study from 2004 that involved hemodialysis patients with chronic kidney failure.

Published in Clinical Nephrology, the paper concluded that, during their dialysis, the patients given a solution high in CO₂ had high levels of glucose diffusion from plasma into erythrocytes. At the time, the researchers said this effect was likely due to the accelerated anaerobic metabolism induced by the changes in the cytoplasmic pH of erythrocytes.

Akira Takahashi, the researcher Tesseikai Neurosurgery Hospital, interrupted these findings to suggest that commercially available carbonated water may also increase glucose metabolism, indirectly promoting weight loss.

He cautions, though, that, in practice, any weight loss achieved by switching to fizzy water would be slight, and other, more proven methods for weight management will be more reliable.

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

“Also, drinking carbonated water can have some effects on the digestive system,” Takahashi warned, “particularly for individuals with sensitive stomachs or pre-existing gastrointestinal conditions.”

Other reactions

While Takahashi has caveated his conclusions, other researchers and dieticians have entirely disputed them.

“Can carbonated water support weight loss? The short answer from this UK dietitian is a robust ‘NO’,” Catherine Collins, an intensive care unit dietitian at the UK’s National Health Service, said in a statement to the UK’s Science Media Centre.

“Dr. Takahashi explores the tiny increase in glucose use by red blood cells when bicarbonate is absorbed from the dialysis fluid during dialysis. He considers whether this slight increase in glucose use by red blood cells during dialysis would increase energy expenditure sufficient to help control weight. This has not been researched.”

“Without empirical data, Dr Takahashi’s suggestion that the bicarbonate generated from carbon dioxide in fizzy water would exert a similarly sized effect on glucose use to that of haemodialysis to boost red blood cell metabolism and generate weight loss is purely speculative.”

“In healthy people, drinking a fizzy drink will have very little effect on blood pH, because typically their bodies are easily buffering blood pH to keep it in the healthy pH 7.35-7.35 range.”

Collins noted, though, that fizzy water could support weight loss in other contexts, such as substituting calorie-rich fizzy sodas in a person’s diet.

“However, substituting zero calorie fizzy water to replace calorific drinks may aid weight loss as part of a calorie-controlled diet, by reducing calorie intake,” she said. “Taking a fizzy drink with meals has in some research reduced calorie intake by inducing feelings of ‘fullness’, but in other studies have shown to increase appetite.”

“Bottom line? Carbonated water is a low-calorie way to rehydrate. But its natural acidity, derived from dissolved CO₂ bubbles, is not as ‘tooth friendly’ as plain water varieties,” Collins concluded.

Reference: Takahashi A. Can carbonated water support weight loss? BMJ NPH. 2025. doi: 10.1136/bmjnph-2024-001108