Are carbonated drinks bad for hydration?

November 17, 2025 •

4 min read

Research indicates that while regular water provides quick hydration, beverages with small amounts of nutrients may hydrate longer. This fact raises a key question: Are carbonated drinks bad for hydration? The answer depends largely on the specific beverage, as factors like sugar and caffeine can significantly alter the hydrating effect.

Quick Summary

Sodas with sugar and caffeine can negatively impact effective hydration, while plain sparkling water hydrates similarly to still water. The presence of specific ingredients determines a carbonated drink's effect on your body's fluid balance.

Key Points

Sugary Sodas Hinder Hydration: High sugar content and caffeine in regular soda can counteract hydration and are not optimal for rehydrating.
Plain Sparkling Water is Hydrating: Plain sparkling water hydrates as effectively as still water, making it a good, flavorless alternative to plain water.
Diet Sodas Have Drawbacks: Diet sodas containing artificial sweeteners, while sugar-free, come with their own set of health concerns and are not an optimal choice for hydration.
Caffeine's Minimal Effect: The caffeine in most sodas has only a mild diuretic effect that is typically outweighed by the fluid intake, especially in regular consumers.
Acids Threaten Dental Health: The high acidity from phosphoric and citric acids in many carbonated drinks can erode tooth enamel and increase the risk of cavities.
Water is the Best Choice: Plain, still water remains the most efficient, calorie-free, and side-effect-free way to hydrate your body effectively.

The Hydration Spectrum: Not All Carbonated Drinks Are Equal

For many, a cold, fizzy drink is a go-to choice for quenching thirst, but not all carbonated beverages are created equal when it comes to hydration. The effect they have on your body's fluid balance depends on what's dissolved in the water.

Sugary Sodas and Hydration

When you consume a regular soda, you're not just drinking water; you're also ingesting a significant amount of sugar. This high sugar content can actually work against the hydration process. As the body works to metabolize the sugar, it pulls water from your cells to dilute the sugar concentration in your bloodstream. This effect can leave you feeling even thirstier and may exacerbate a state of dehydration, especially if you were already thirsty. Many sodas also contain caffeine, a mild diuretic that promotes urine production and can increase fluid loss. While the amount of caffeine in a typical soda is usually not enough to cause significant dehydration in most people, its diuretic effect can still counteract your hydration efforts, making water a far more efficient choice. For athletes or individuals trying to rehydrate quickly, sugary and caffeinated sodas are particularly ineffective and potentially counterproductive.

Sparkling Water and Hydration

In contrast to sugary sodas, plain sparkling water is an excellent and equally hydrating alternative to still water. Its base ingredient is simply water, with the added carbon dioxide having no impact on the body's ability to absorb and utilize the fluid for hydration. The fizz, however, can cause some individuals to feel bloated or full faster than they would with still water, potentially leading them to drink less overall. This feeling of fullness can be a minor drawback for some, but for those who find the taste of plain water unappealing, sparkling water can be a more enjoyable way to increase daily fluid intake. Choosing unsweetened flavored options can also help curb cravings for sugary beverages without sacrificing hydration benefits.

Diet Sodas and Artificial Sweeteners

Diet or 'zero-calorie' sodas, while free of sugar, introduce a different set of issues. They typically contain artificial sweeteners like aspartame or sucralose. While the hydration impact of these beverages is less clear than that of sugary sodas, artificial sweeteners have been linked to other health concerns related to metabolism and gut health. Furthermore, relying on diet sodas can perpetuate a preference for overly sweet tastes, making it harder to appreciate plain water over time. Therefore, even diet sodas are not the optimal choice for true, no-strings-attached hydration.

Beyond Hydration: Other Health Impacts of Carbonated Drinks

Beyond their direct effect on fluid balance, carbonated drinks can affect overall health in several ways.

Dental Health Concerns

The high acidity in many carbonated drinks, particularly those containing phosphoric or citric acid, can be damaging to tooth enamel. This acid erosion increases the risk of cavities and tooth sensitivity over time. While all carbonated drinks are slightly acidic due to the carbonic acid formed from dissolved CO2, flavored and cola sodas often contain additional acids that worsen this effect.

Bone Health and Mineral Balance

Certain dark colas contain high levels of phosphoric acid, which some studies have linked to a reduction in bone mineral density. Excessive phosphorus intake can disrupt the body's natural balance of calcium and phosphorus, potentially leading to bone loss. This risk is especially relevant for adolescents and elderly individuals who are already susceptible to bone density issues.

Digestive System Effects

The carbon dioxide gas in fizzy drinks can cause bloating, belching, and gas, especially for individuals with sensitive digestive systems or conditions like IBS. This can lead to uncomfortable fullness that can interfere with normal daily activities. Plain, still water is a much gentler option for the gut and does not carry this risk of gas-related discomfort.

Comparison: Water vs. Common Carbonated Drinks


Feature	Plain Water	Sugary Soda	Plain Sparkling Water
Hydration Potential	Excellent	Poor	Excellent
Sugar Content	0g	High (e.g., ~39g/12 oz)	0g
Calorie Count	0	High (e.g., ~140/12 oz)	0
Caffeine	None	Often present	None
Electrolytes	Trace minerals (variable)	None added	Trace minerals (variable)
Dental Impact	Negligible	High risk (acid + sugar)	Low risk (acid only)
Bloating Risk	None	High	Moderate

What to Drink for Optimal Hydration

For most people, the best choice for daily hydration is plain, still water. It’s calorie-free, easily absorbed, and effectively replenishes lost fluids. For those who find water boring, plain sparkling water with no added sugar or artificial sweeteners is a valid and hydrating alternative. The key is to check the label for any hidden sugars or additives. For athletes with high sweat loss, an electrolyte-rich sports drink can be beneficial, though most people can replenish lost electrolytes through a balanced diet. Ultimately, fizzy drinks—especially sugary ones—should be viewed as an occasional treat rather than a primary source of hydration.

Conclusion: The Bottom Line on Fizzy Drinks and Hydration

In summary, the notion that all carbonated drinks are inherently bad for hydration is a simplification. The hydrating power depends heavily on the ingredients. While plain sparkling water hydrates effectively, sugary and caffeinated sodas are suboptimal choices due to their counteracting effects on fluid balance. High sugar content requires the body to expend water for metabolism, while caffeine has mild diuretic properties. Other risks like dental erosion, reduced bone mineral density, and digestive discomfort further underscore that sugary sodas and colas are not healthy hydration sources. For optimal health and rehydration, prioritize plain water and enjoy other carbonated options in moderation.

For more information on caffeine and hydration, consult resources from trusted health organizations like the Mayo Clinic: Mayo Clinic - Caffeine.

Frequently Asked Questions

At typical soda levels, caffeine's diuretic effect is usually minimal and is often outweighed by the fluid consumed. However, for those unaccustomed to caffeine or consuming large amounts, it can lead to increased urination and affect fluid balance.

Yes, plain sparkling water is scientifically proven to be just as hydrating as regular still water. The added carbonation does not interfere with your body's ability to absorb water effectively.

The high sugar content in sugary sodas forces your body to use more water to metabolize it, which can actually leave you feeling thirstier and can detract from overall hydration efforts.

Yes, the carbon dioxide gas that gives carbonated drinks their fizz can get trapped in your stomach and digestive tract, leading to a feeling of fullness and bloating, especially in sensitive individuals.

While they lack the calories and sugar of regular sodas, diet sodas are not an optimal choice for hydration due to the presence of artificial sweeteners and their lack of nutritional value. Plain water is still the superior choice.

Excessive consumption of phosphoric acid, commonly found in dark colas, has been linked to negative health effects such as reduced bone mineral density and potential kidney issues over time.

No, it is not ideal. During strenuous activity, your body needs to replenish fluids and electrolytes quickly. Plain water is best, and a sports drink with electrolytes is better than a sugary soda, which can hinder rehydration.