Does Cola zero count as water? The complete hydration guide

December 18, 2025 •

3 min read

While a typical can of Coke Zero is composed of over 99% water, the question remains: does cola zero count as water for meeting your daily fluid needs? The answer is more complex than a simple yes or no, involving a trade-off between hydration and overall health.

Quick Summary

Cola Zero is mostly water and contributes to fluid intake, but its added ingredients and lack of nutritional value mean it isn't a healthy substitute for pure water. Potential health concerns include dental erosion and long-term effects of artificial sweeteners.

Key Points

Mostly Water: Cola Zero is composed of over 99% water, so it does technically contribute to your fluid intake for the day.
Mild Diuretic Effect: The caffeine in cola has a mild diuretic effect, but the amount is generally not enough to cause net dehydration, especially in regular consumers.
No Nutritional Value: Unlike water, Cola Zero offers no nutritional benefits, as it is calorie-free but also devoid of essential vitamins and minerals.
Dental Risks: The high acidity from phosphoric acid in Cola Zero can erode tooth enamel over time, posing risks to dental health.
Potential Health Concerns: Long-term consumption of artificial sweeteners has been linked to potential issues with gut health, metabolic syndrome, and other conditions in some studies.
Water is Superior: For optimal hydration and overall health, plain water is the best choice due to its purity and lack of potentially harmful additives.
Consider Alternatives: Healthier options for flavored drinks include fruit-infused water, unsweetened tea, or naturally flavored seltzer.

The Basic Answer: Yes, But It’s Not That Simple

At its most basic level, Cola Zero is primarily composed of carbonated water. This means that when you drink it, you are, in fact, consuming a liquid that your body can use for hydration. Some studies even show that the hydration effect of diet soda is comparable to other common beverages like coffee or tea. The main reason is that the sheer volume of water in the drink far outweighs the effects of its other ingredients, including caffeine.

The Mild Diuretic Effect of Caffeine

One common misconception is that the caffeine in Cola Zero will immediately dehydrate you. While caffeine is a mild diuretic, meaning it can increase urine production, the effect is not strong enough in moderate doses to override the hydrating effect of the water content. For most regular consumers, the body develops a tolerance to caffeine's diuretic properties. The amount of caffeine in a single can of cola is generally low enough that the net effect is still hydrating. However, relying solely on caffeinated beverages for your fluid intake is still not recommended.

Why Cola Zero Isn't a True Water Substitute

Despite its high water content and mild hydrating effect, health professionals do not consider Cola Zero an adequate replacement for water. The fundamental difference lies in its nutritional profile and added ingredients, which provide no health benefits and carry potential risks.

Artificial Sweeteners and Gut Health

Cola Zero contains artificial sweeteners such as aspartame and acesulfame potassium to achieve its sweet flavor without calories. While regulatory bodies like the FDA consider them safe within acceptable daily intake levels, some research suggests potential negative impacts on gut health.

Dental and Bone Health Risks

The high acidity of sodas due to ingredients like phosphoric acid can erode tooth enamel, increasing the risk of cavities. High intake of phosphoric acid has also been linked to potential negative effects on bone density. Plain water does not carry these risks.

Potential for Weight Gain

Some studies have linked diet soda consumption to weight gain and increased waist size, possibly due to artificial sweeteners increasing cravings for sweet foods. Water, conversely, can aid in weight management.

Comparing Cola Zero and Water


Feature	Cola Zero	Water
Hydration	Yes, provides hydration, but with other ingredients.	The most effective and pure form of hydration.
Nutritional Value	Zero nutritional value; contains no vitamins or minerals.	Essential for all bodily functions; contains no calories or sugar.
Taste	Artificially sweetened and flavored; highly acidic.	Neutral taste; can be infused naturally with fruit.
Additives	Contains artificial sweeteners, phosphoric acid, and other chemicals.	No additives, pure, and natural.
Dental Health	High acidity can lead to tooth enamel erosion.	Neutral pH is beneficial for dental health.
Long-Term Health	Linked to potential risks for heart disease, kidney issues, and metabolic syndrome in some studies.	Offers significant, scientifically-backed health benefits.

Healthier Alternatives to Consider

If you want a flavorful drink without the artificial ingredients, consider:

Flavored Seltzer Water: Carbonated water with natural fruit essences.
Fruit-Infused Water: Water with added fresh or frozen fruits.
Unsweetened Iced Tea: A source of antioxidants where you control the sweetness.
Kombucha: Fermented tea with potential gut health benefits (check sugar content).

Conclusion: Prioritize Pure Water

While Cola Zero provides fluid intake, its artificial ingredients offer no nutritional value and pose potential health risks, unlike pure water. Water remains the optimal choice for hydration and health. Healthier alternatives exist for those who prefer flavored or carbonated beverages. Cola Zero is best enjoyed in moderation as an occasional drink, not a primary source of hydration.

What to drink instead of Coke Zero

Occasional Coke Zero is acceptable, but not recommended for daily consumption due to potential health risks. Healthier alternatives include fruit-infused water, unsweetened tea, kombucha, or plain carbonated water. Fruit juice can also be an option, but be mindful of added sugars.

Frequently Asked Questions

Coke Zero is hydrating because its high water content outweighs the mild diuretic effect of its caffeine. However, it is not as healthy or effective for hydration as pure water due to its other additives.

No, you should not replace all your water intake with Cola Zero. While it provides fluid, it lacks nutritional value and contains ingredients like artificial sweeteners and acids that can have negative long-term health effects.

Diet sodas eliminate the high sugar and calorie load of regular sodas, but they introduce other concerns related to artificial sweeteners and acids. For overall health, both are best consumed in moderation, but diet soda is generally a better choice than regular for those watching sugar and calorie intake.

The phosphoric acid in Cola Zero can erode tooth enamel due to its high acidity. This can increase the risk of cavities and tooth sensitivity over time, an issue not present with water.

The best alternatives are options like fruit-infused water, plain seltzer with natural flavor essences, or unsweetened iced tea. These provide flavor and effervescence without artificial sweeteners or high acidity.

The relationship between artificial sweeteners and weight is complex and research is mixed. Some observational studies link diet soda consumption to weight gain, possibly by increasing cravings, while other experimental studies show replacement of sugary drinks with diet soda can result in weight loss.

Some observational studies have linked excessive consumption of diet soda to an increased risk of kidney disease, potentially due to the high phosphorus content. However, more research is needed to fully understand this connection.