Essential Information on Carbonated Water and Weight Reduction

Fizzy, sparkling, carbonated, or seltzer—regardless of the terminology, water that stimulates the nasal passages is enjoyable and invigorating, and for some, a desirable alternative to its non-carbonated counterpart.

Sparkling water has garnered a following on social media due to its effects on body mass. Certain individuals assert that carbonated water may contribute to weight gain, referencing a February 2017 study that indicated that carbonated beverages enhance appetite by elevating ghrelin, the hormone associated with hunger. Nonetheless, that study was conducted on male rats and involved only 20 individuals, and it has never been reproduced.

The prevailing theory suggests that carbonated water may facilitate weight loss. Carbonated bubbles may enhance the sensation of satiety, whereas water facilitates fat oxidation by elevating metabolism; indeed, water is essential for lipolysis, the process through which the body converts stored fat into energy.

A recent study investigates a third rationale: Carbonated water may help reduce blood glucose levels. Experts assert that maintaining stable blood sugar levels, with minimal fluctuations, is advantageous for weight loss, as it enables the body's cells to more efficiently utilize fat for energy between meals.

“When carbonated water is consumed, CO2 is absorbed into the blood vessels in the stomach,”

stated study author Dr. Akira Takahashi, a physician in the dialysis center at Tesseikai Neurosurgical Hospital in Shijonawate, Japan, in an email.

While some carbonated water is natural, formed as volcanic gases infuse the water in natural springs with bubbles and minerals, most sparkling water is made by pushing carbon dioxide, or CO2, into water under extreme pressure.

Once in the circulation, CO2 is swiftly transformed into bicarbonate ions as part of a process that maintains pH balance. This reaction then causes red blood cells to become more alkaline, Takahashi explained. This increased alkalinity increases the process of glucose consumption in red blood cells, therefore reducing glucose levels.

No considerable weight loss

The study, published Tuesday in the journal BMJ Nutrition, Prevention & Health, was built upon 2004 research by Takahashi and his team on hemodialysis, a process that occurs during kidney dialysis when blood is filtered to eliminate waste and excess water. During hemodialysis, CO2 enters the blood, exactly as it does when carbonated water is drunk.

While the November 2004 study did reveal blood sugar levels decline when CO2 is introduced to blood, the new study found the amount of glucose burned during this procedure would not be enough for any meaningful weight loss.

“Red blood cells cannot fully ‘burn’ the glucose, and it will be recycled by the liver,”

said Keith Frayn, a professor emeritus of human metabolism at the University of Oxford in the UK, who was not involved in the study.

“If fizzy drinks were to be shown to lead to weight loss, it would much more likely be through effects on feelings of fullness,”

Frayn said in a statement. “In the meantime, however, sugar-sweetened fizzy drinks are recognized as a source of excess calories and likely to do just the opposite.”

In addition, blood sugar levels were only temporarily dropped, Takahashi added, and the carbonated water would have a small effect on calorie consumption.

“Therefore, carbonated water alone is unlikely to contribute significantly to weight loss,” he stated. “A balanced diet and regular exercise remain essential for effective weight management.”

Use for optimal health

Studies have revealed persons who drank two cups of water before meals lost more weight than those who did not. Another study found participants who replaced diet beverages with water also benefited by shedding pounds.

“Some of the patients I see for weight loss never feel satisfied,” said Welstead, who was not involved in the current study. “These are the folks who tell me, ‘I’m always hungry and I’m always waiting for a snack,’ and I think it can really help some of those people.”

Still, filling your belly with bubbly water can increase satiety and may be especially helpful for people who struggle with hunger pains, said registered dietitian Lori Welstead, who specializes in gastrointestinal nutrition at the University of Chicago Medicine, a not-for-profit academic medical health system.

“But be mindful of excess or added sugars, including some of the fake sugars, because those may be negative metabolically,” she cautioned.

Other patients believe they benefit from fizzy liquids because the bubbles help clear their esophagus and stomach and move food along in the digestive tract, she said.

“Some people with a ‘slow’ stomach, so to speak, find carbonation helps with their gut motility,” Welstead added. “So we have some people for whom these sparkling or tonic waters can createfullness, and others for whom it helps with digestion.”

But don’t overdo it, she adds - more than one or two sparkling waters a day could severely increase gas and abdominal pain from the carbonation.

“If someone’s coming in and they’re saying, ‘Oh my gosh, I’m gassy, I’m bloated, I’m burping, I’m feeling so sick all day,’ it could be due to drinking five cans of carbonated water each day.”