Sparkling water and seltzers are often seen as a healthier alternative to soda because they don’t contain sugar or artificial sweeteners. For those seeking to lose weight, the allure of a simple beverage that could potentially contribute to their goals is strong. But can fizzy water truly aid in weight loss? Recent research has explored this question, looking at potential mechanisms and effects.
The Claim: Can Fizzy Water Boost Metabolism and Aid Weight Loss?
One recent report highlights that drinking carbonated or sparkling water may contribute to weight loss by increasing red blood cell uptake and glucose metabolism. A report published in BMJ Nutrition, Prevention & Health discussed how drinking sparkling water may contribute to weight loss, suggesting that the CO2 in the water leads to increased glucose breakdown and increased glucose uptake by red blood cells. Thus, sparkling water could indirectly help weight loss through its effect on blood glucose.
The report begins by noting a few ways that drinking sparkling water may help with weight loss. For example, drinking sparkling water may lead to increased feelings of fullness. The report notes that it may also lower blood sugar levels but that the mechanisms are not entirely clear.
The Science Behind the Fizz: How Carbonated Water Might Affect Blood Glucose
After sparkling water is consumed, CO2 goes through the stomach capillaries into the bloodstream. From here, the red blood cells use an enzyme called carbonic anhydrase to convert the CO2 into bicarbonate (HCO3-). Next, the interior of the red blood cells ultimately becomes alkaline or less acidic. This leads to an increase in the breakdown of glucose by the red blood cells to produce energy, a process called glycolysis. This is believed to promote glycolysis and increase the red blood cells’ glucose uptake from the plasma.
The report compares this process to the similar lowering of blood sugar that occurs in hemodialysis, the filtering of the blood. It references a previous paper published in 2004 that discussed how hemodialysis may lead to lowered blood sugar. Haemodialysis turns blood alkaline, primarily producing carbon dioxide (CO₂). Similarly, the CO₂ of fizzy water is absorbed through the stomach lining and is rapidly converted to bicarbonate (HCO3) in red blood cells.
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Report author Akira Takahashi with the Dialysis Center at Tesseikai Neurosurgery Hospital in Shijonawate, Japan, highlighted the main points of the report this way: “When carbonated water is consumed, CO₂ is absorbed into the blood vessels in the stomach. This CO₂ rapidly penetrates the lipid membranes of red blood cells and is converted into bicarbonate ions by carbonic anhydrase, increasing the alkalinity of the red blood cells. This alkalinity promotes glycolysis, which consumes glucose in red blood cells and lowers blood glucose levels.”
Is the Effect Significant? A Word of Caution
However, the report notes that the effects are so minimal that carbonated water is unlikely to have a significant impact on weight loss on its own. The effects of sparkling water on metabolism are small, and drinking fizzy water on its own without making any other diet or exercise changes isn’t likely to help anyone lose weight, the research concluded.
Takahashi writes: “It is important to note that carbonated water alone is unlikely to contribute significantly to weight loss."
Mir Ali, MD, board certified general surgeon, bariatric surgeon, and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, commented the following about the study to Medical News Today: “This is an interesting study, though it is theoretical and requires clinical research in people comparing consumption of carbonated water vs non-carbonated water. If studies in humans show a benefit of carbonated water, then it may be an adjunct to a healthy diet.”
When comparing it to what occurs in hemodialysis, Takahashi noted the following: “During a four-hour session of hemodialysis, only about 9.5g of glucose is consumed. Since drinking carbonated water provides CO₂ for a much shorter period than hemodialysis, its effect on glucose consumption is negligible and does not contribute to weight loss.”
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Thus, the paper emphasizes that drinking sparkling water should not be a standalone strategy for losing weight and that eating a balanced diet and exercising remain important components.
The Fullness Factor: Does Fizzy Water Curb Appetite?
Another claim that has sometimes been made about fizzy water is that it can help you feel fuller for longer, which may aid in weight loss. There’s some research to suggest that the carbonation found in sparkling water increases satiety more than other fluids by increasing stomach distension. Anecdotally, most people do report increased stomach distention after drinking carbonated drinks, so the concept that it can increase satiety without increasing calories is valid. Usually people don’t like bloating, but that feeling of fullness can lead them to eat smaller portions or avoid unnecessary snacking.
Gabby Zeagler, clinical dietitian at Nourish, noted that carbonated water can create a feeling of fullness that may help reduce your appetite and allow you to be satisfied with less food at your next meal.
The Counterpoint: Does Fizzy Water Increase Hunger?
While some studies have found that people who drank carbonated water reported it helped them feel fuller for longer, other studies have actually shown it may have the opposite effect. Research in rats that looked specifically at weight and appetite hormones found that sparkling water increased both weight and levels of the hunger hormone ghrelin. In a parallel study these researchers conducted on 20 men, it was shown that fizzy water also increased their ghrelin levels.
One study that included lab rats and 20 humans concluded that carbonated drinks increased the hormone. People who drank either unsweetened or artificially sweetened carbonated drinks had triple the blood levels of ghrelin compared with those who drank plain or degassed sparkling water.
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It seems the data is not conclusive about the effect of fizzy water on hunger.
Other Potential Benefits of Fizzy Water
As pointed out in this report, drinking sparkling water may offer certain benefits, but it may also have certain drawbacks. “The potential benefits are largely unknown, though there have been some studies that show carbonated water may aid in constipation relief,” Ali noted.
Zeagler wasn’t involved in the study. “If someone is drinking seltzer all day long, this will also increase their hydration level which helps support metabolism and will likely reduce the amount of times someone may mistake a feeling of thirst for hunger and lessen the amount of snacking they might do,” she said.
Carbonated water is also a great substitute for soda, juice, and other sugary, high-calorie beverages, according to Zeagler, which will help you take in fewer calories over the course of the day. For some people, carbonated water can help with digestion, and when our stomach is feeling less bloated, we are more likely to follow a healthful eating pattern.
Potential Drawbacks and Considerations
He suggests the potential downsides of drinking carbonated water include bloating and gas. The paper emphasizes that drinking sparkling water should not be a standalone strategy for losing weight and that eating a balanced diet and exercising remain important components. It also notes that drinking sparkling water can negatively affect the digestive system, so moderation is important. Additionally, it could lead to temporary drops in blood sugar levels and affect blood sugar measurements taken while drinking these beverages.
“Also, drinking carbonated water can have some effects on the digestive system, particularly for individuals with sensitive stomachs or pre-existing gastrointestinal conditions.
The Importance of a Holistic Approach to Weight Loss
However, she agreed with the study author, and noted fizzy water is not “a magical drink.”
“Drinking fizzy water is just part of the equation for effective weight loss,” explained Jonathan Kaplan, MD, founder and CEO of Dr. Well by BuildMyHealth. “It could be used as an alternative to high-calorie drinks, but to achieve real progress, it must be used in conjunction with diet and exercise.”
Kaplan suggested eating a diet rich in lean proteins, fiber, and healthy fats. These will keep you full longer and help you maintain muscle while you are losing fat.
Stress management and good sleep also play a vital role in your weight loss, according to Kaplan. This helps regulate the hunger hormones, such as cortisol and leptin.
In addition to these measures, Zeagler suggested practicing mindful eating. “Pay attention to hunger cues, eat slowly, and avoid distractions during meals. Put your phone away while eating!” she advised.
She also suggested tracking your progress, whether with a food journal, app, or wearable device. “This way, you can identify areas for improvement and improve upon them,” said Zeagler. “Remember, you can’t improve what you don’t measure.”