Understanding Zero Sugar Drinks: How many calories do zero sugar drinks have?

October 24, 2025 •

4 min read

The US Food and Drug Administration (FDA) legally allows manufacturers to label any product with fewer than five calories per serving as “zero calorie”. This fact reveals that the answer to how many calories do zero sugar drinks have isn't as straightforward as it seems, because while they contain no sugar, they may still contain trace calories.

Quick Summary

Zero sugar drinks have negligible calories, thanks to artificial sweeteners that pass through the body without being absorbed. However, FDA rounding rules mean a serving can contain up to five calories and still claim to have zero.

Key Points

Legally Zero, Practically Insignificant: Under US law, a product with fewer than five calories per serving can be labeled as having zero calories, meaning zero-sugar drinks are not entirely calorie-free, but any energy they contain is minimal.
Sweetened, Not Absorbed: Zero-sugar drinks use artificial sweeteners like aspartame and sucralose that taste sweet but are not absorbed by the body for energy, hence their low-to-no calorie count.
Correlation vs. Causation: Observational studies linking zero-sugar drinks to negative health outcomes often show correlation, not causation, with other lifestyle factors potentially at play.
Potential Gut Health Impact: Research on artificial sweeteners and the gut microbiome has produced mixed results, with some studies suggesting a negative impact on beneficial gut bacteria.
Not a Nutritional Silver Bullet: Despite having zero sugar and calories, these drinks provide no nutritional value and should not be considered a healthy substitute for water or other naturally healthy beverages.
Beware of Phosphoric Acid: The acids used in zero-sugar sodas, like phosphoric acid, can still contribute to tooth enamel erosion and potentially impact kidney health with high consumption.

The Science Behind "Zero Calories"

Many consumers choose zero-sugar drinks, such as Diet Coke or Coca-Cola Zero Sugar, as a strategy for reducing calorie intake without sacrificing flavor. The marketing of these products as having "zero calories" is a common and legally permissible practice under FDA regulations, but it is a claim that warrants a closer look.

Under US food labeling guidelines, if a serving contains fewer than five calories, a manufacturer can round the number down to zero. This means that while a 12-ounce can of Coke Zero or a similar product lists 0 calories on its label, it might contain a minute amount of energy. However, this small amount is generally considered nutritionally insignificant. The true secret to their lack of caloric energy lies in the artificial or non-nutritive sweeteners used, which provide intense sweetness without the caloric baggage of sugar.

Artificial Sweeteners: The Zero-Calorie Ingredients

Zero-sugar drinks get their sweet taste from a variety of sugar substitutes. Unlike sucrose (table sugar), these compounds are not metabolized by the body for energy and thus contribute virtually no calories. Some of the most common sweeteners include:

Aspartame: Composed of two amino acids, it is about 200 times sweeter than sugar. It is metabolized into its component parts but provides very few calories due to the minuscule amount needed.
Acesulfame Potassium (Ace-K): Often used in combination with other sweeteners, it is also roughly 200 times sweeter than sugar. It is not metabolized by the body and is excreted unchanged.
Sucralose: A chlorinated sucrose derivative that is around 600 times sweeter than sugar. Like Ace-K, most of it passes through the body without being absorbed.
Stevia: Derived from the stevia plant, these extracts can be 100 to 300 times sweeter than sugar. They are degraded by gut microbiota, but without significant caloric contribution.

Zero-Sugar vs. Regular Drinks: A Nutritional Comparison

To highlight the difference, consider a standard 12-ounce serving of regular and zero-sugar cola.


Feature	Regular Cola (e.g., Classic Coke)	Zero-Sugar Cola (e.g., Coke Zero)
Calories	~150-160 calories	0 calories (negligible)
Sugar	~40 grams	0 grams
Carbohydrates	~40 grams	0 grams
Sweetener	High-fructose corn syrup or sugar	Aspartame, Acesulfame Potassium
Nutritional Value	None (empty calories)	None

The Full Picture: Potential Health Implications

While zero-sugar drinks offer a clear advantage in calorie savings, the broader health implications are a subject of ongoing debate and research. The World Health Organization (WHO) has recommended against using non-nutritive sweeteners for weight control due to insufficient evidence of long-term benefits.

Impact on Weight Management: Some observational studies have linked diet soda consumption with an increased risk of obesity and higher waist circumference over time. Some researchers propose that artificially sweetened beverages may increase cravings for high-calorie, sweet foods. However, other studies, particularly controlled trials, suggest replacing sugary drinks with diet versions can aid weight loss. This contradiction may be explained by reverse causation, where people already at risk for obesity or with poor eating habits are more likely to choose diet drinks.
Gut Microbiome: A healthy gut microbiome is crucial for overall health, and there is growing evidence that artificial sweeteners can alter the balance of gut bacteria. Some research suggests sweeteners like sucralose and saccharin might negatively affect healthy gut flora, while polyols like erythritol may have a prebiotic effect. However, results are inconsistent across studies, emphasizing the need for more research.
Metabolic and Cardiovascular Health: Observational studies have reported a correlation between frequent artificial sweetener intake and an increased risk of type 2 diabetes and cardiovascular events like stroke. A 2023 review associated artificial sweeteners with hypertension and insulin resistance. It is important to note that these studies show correlation, not direct causation. Confounding factors, such as pre-existing health conditions or lifestyle choices, can influence the results.
Dental Health: Unlike sugary sodas that can lead to tooth decay, artificial sweeteners do not react with oral bacteria to produce enamel-damaging acids. However, the phosphoric acid present in many zero-sugar colas can still contribute to tooth erosion.
Other Considerations: Some individuals report headaches, mood changes, or digestive issues from certain artificial sweeteners. Furthermore, the phosphoric acid in many sodas has been linked to potential kidney issues with excessive consumption.

Healthy Alternatives to Zero-Sugar Drinks

For those looking to reduce or eliminate zero-sugar and artificially sweetened drinks, several healthy alternatives can help you stay hydrated and refreshed:

Water with a Twist: Add slices of fresh fruit (lemon, lime, berries) or herbs (mint, basil) for natural flavor.
Herbal Teas: Unsweetened herbal teas, served hot or cold, offer a calorie-free, flavorful drink with potential antioxidant benefits.
Kombucha: This fermented tea contains probiotics that support gut health, but it's important to choose lower-sugar options.
Sparkling Water: Plain carbonated water is a great option for those who enjoy fizz, but look for brands without added sweeteners or flavorings.

Conclusion

For the vast majority of consumers, zero-sugar drinks contain a negligible amount of calories, making them a useful tool for reducing overall sugar intake. However, framing them as a universally healthy choice overlooks the complex and sometimes conflicting evidence regarding their long-term health effects. Concerns surrounding their potential impact on gut health, metabolic processes, and appetite regulation mean they should not be seen as a nutritional cure-all. Instead, moderation is key, and opting for water or naturally flavored alternatives remains the healthiest choice. Ultimately, zero-sugar beverages can serve as a temporary bridge away from sugary drinks, but they are not a substitute for a balanced, whole-food diet.

Frequently Asked Questions

A product can be labeled 'zero calorie' in the U.S. if it contains fewer than five calories per serving, according to FDA regulations. The ingredients that provide flavor, such as artificial sweeteners, contribute negligible or no calories because the body does not metabolize them for energy.

Research on the long-term metabolic effects of artificial sweeteners is mixed. Some studies suggest they may alter the gut microbiome and potentially affect appetite or insulin response, while other controlled trials show no significant impact.

Some observational studies have shown a link between diet soda consumption and weight gain or larger waist circumference. This might be due to reverse causation (people at risk of obesity drinking diet soda) or other factors like increased cravings for sweet foods, but it's not a settled conclusion.

Technically, a 12-ounce can of Coke Zero contains slightly less than 5 calories, which allows it to be labeled as 0 calories under US FDA rules. It uses artificial sweeteners like aspartame and acesulfame potassium instead of sugar.

Some studies, particularly in rodents, have suggested that artificial sweeteners can disrupt the balance of gut bacteria, potentially affecting metabolic health. However, human studies are less conclusive and more research is needed.

Healthier alternatives include plain water, fruit-infused water, and unsweetened herbal teas. These options provide hydration without any artificial sweeteners or other potentially controversial additives.

Yes, many zero-sugar and diet sodas contain phosphoric and citric acids, which can erode tooth enamel over time, just like their sugary counterparts. Sipping through a straw can help minimize contact with teeth.