How Many Cans of Diet Soda Can I Drink a Day?

October 11, 2025 •

3 min read

According to the World Health Organization (WHO), long-term use of non-sugar sweeteners may have potential undesirable effects, including an increased risk of type 2 diabetes and cardiovascular diseases. So, how many cans of diet soda can I drink a day, given these findings?

Quick Summary

This article explores the acceptable daily intake guidelines for common artificial sweeteners found in diet soda, discussing potential health risks and offering healthier beverage alternatives.

Key Points

Moderation is key: Most health experts recommend limiting diet soda to one can per day, despite much higher official 'safe' limits based on artificial sweetener levels.
ADI does not mean healthy: The acceptable daily intake (ADI) for sweeteners like aspartame is very high but does not imply that drinking large amounts of diet soda is healthy or without risk.
Potential health risks exist: Regular, long-term consumption has been linked to increased risk of metabolic syndrome, type 2 diabetes, weight gain, and other health issues in observational studies.
Prioritize healthier alternatives: Water, unsweetened tea, and plain sparkling water are nutritionally superior choices for hydration and overall health.
Consider the 'why': Ask if you're drinking diet soda out of habit or for a perceived benefit, and transition to healthier drinks gradually to reduce dependency.
Nutritional value is zero: Unlike water or milk, diet soda provides no vitamins, minerals, or other nutritional benefits to your diet.
Diet soda is still acidic: The acids in diet soda, not just the sweeteners, can cause dental erosion over time.
Correlation is not causation: While many studies show a link between diet soda and negative health outcomes, a direct cause-and-effect relationship has not always been definitively proven, though the evidence warrants caution.

Understanding the 'Safe' Limits of Diet Soda

When considering how many cans of diet soda can I drink a day, it's crucial to understand the acceptable daily intake (ADI) levels set by health authorities for the artificial sweeteners they contain. The ADI is the maximum amount of a substance consumable daily over a lifetime without significant health risk.

Regulatory bodies like the FDA and JECFA have evaluated sweeteners such as aspartame and sucralose. The ADI for aspartame is 50 mg/kg body weight, equating to about 9–14 cans of diet soda daily for a 150-pound person. The FDA's ADI for sucralose is 5 mg/kg body weight per day. While these ADI values are high, experts generally recommend much lower intake, often suggesting no more than one can per day.

The Problem with Defining a Safe Daily Limit

Providing a precise number of daily diet soda cans is challenging because the concern extends beyond just reaching a single sweetener's ADI. Regular, long-term consumption has been linked in observational studies to negative health outcomes. For instance, daily artificially sweetened soda consumption was associated with a higher risk of type 2 diabetes in a 2018 study. Critics note that correlation doesn't prove causation and that other risk factors might be involved, but these links warrant caution.

Potential Health Concerns Associated with Diet Soda

Metabolic Syndrome and Diabetes: Linked to increased risk, possibly by affecting insulin response.
Weight Gain and Obesity: Studies show associations, potentially due to increased cravings or being a choice for those with less healthy diets.
Heart Health: Regular intake linked to higher risk of cardiovascular issues, especially in certain groups.
Kidney Issues: Excessive consumption associated with increased risk of chronic kidney disease, potentially due to ingredients like phosphorus in dark sodas.
Dental Erosion: Acidity can damage tooth enamel.
Altered Gut Microbiome: Artificial sweeteners may disrupt gut bacteria balance, with variable individual effects.

Comparative Table: Diet Soda vs. Healthier Alternatives


Beverage Type	Calories	Sweeteners	Potential Health Impact	Cost (Approx.)
Diet Soda	0-5 kcal	Aspartame, Sucralose, etc.	Linked to metabolic syndrome, weight gain, and cardiovascular risk. No nutritional value. Can erode teeth.	Low
Water	0 kcal	None	Essential for hydration and all bodily functions. No negative health impacts. Supports weight management.	Very Low
Sparkling Water (Unflavored)	0 kcal	None	A great alternative for the 'fizz'. Non-erosive to teeth compared to soda. Supports hydration.	Low to Moderate
Unsweetened Tea (Hot or Iced)	0-2 kcal	None	Contains antioxidants. Can be caffeinated or herbal. A good replacement for the caffeine fix.	Low
Fruit-Infused Water	0-10 kcal	Natural fruit sugars	Adds flavor without artificial ingredients. Hydrating. Nutrient content depends on fruit added.	Low to Moderate

Reducing Your Dependence on Diet Soda

Reducing diet soda intake is possible with a plan:

Introduce Alternatives Gradually: Swap one diet soda daily for sparkling water or unsweetened tea, adding fruit juice for flavor if needed.
Focus on Hydration: Drink plenty of plain water throughout the day.
Find Your 'Fizzy' Fix: Try plain or naturally flavored sparkling waters with fruit slices.
Try Natural Sweeteners (with caution): Use stevia in moderation in water or tea.
Address the Caffeine: Switch to unsweetened black or green tea for a caffeine boost.

Conclusion

A precise daily limit for diet soda is difficult to define due to varying research and individual health. However, a conservative approach is recommended, with many experts suggesting no more than one can per day. The WHO advises against long-term reliance on non-sugar sweeteners for health benefits. While ADI values for sweeteners are high, they don't negate observational links to health risks. Diet soda lacks nutritional value and carries potential risks with regular consumption. Prioritizing water, sparkling water, and unsweetened teas is the best strategy for optimal health.

For more information on sweeteners, refer to sources like the FDA.

Authoritative Source

FDA: Additional Information about High-Intensity Sweeteners

Frequently Asked Questions

For most healthy individuals, consuming one can of diet soda per day is unlikely to cause serious harm, as this falls well below the officially established Acceptable Daily Intake (ADI) for most artificial sweeteners. However, health experts still recommend moderation and prioritizing more nutritious beverages like water.

The relationship between diet soda and weight gain is complex. Some observational studies have linked diet soda consumption to weight gain and obesity, while some experimental studies have shown weight loss when switching from regular soda. Theories suggest artificial sweeteners may alter hunger signals, but research is mixed. It's often debated whether diet soda causes weight gain or if individuals with unhealthy dietary habits are more likely to drink it.

While diet soda does not contain sugar, artificial sweeteners can have a complex effect. Some studies suggest they may alter insulin sensitivity or resistance over time, while others have found no effect on blood sugar levels. For individuals with diabetes, moderate intake may be fine, but consultation with a doctor and regular monitoring is essential.

Long-term consumption of diet soda has been linked in observational studies to an increased risk of metabolic syndrome, type 2 diabetes, cardiovascular disease, and kidney problems. The World Health Organization advises against the long-term use of non-sugar sweeteners for weight control due to potential undesirable effects.

There is no single diet soda universally identified as the 'worst.' Concerns are often related to the artificial sweeteners used (like aspartame or sucralose) or ingredients like phosphoric acid, which is found in many dark colas and can harm kidneys in excessive amounts. Variety and moderation are better strategies than singling out a specific brand.

Regulatory bodies like the FDA and JECFA have affirmed the safety of aspartame when consumed within the established ADI. The recent classification of aspartame as 'possibly carcinogenic to humans' by the IARC was a hazard identification, not a risk assessment, and does not mean it is necessarily carcinogenic at normal consumption levels. The dose makes the poison, and most people consume far below the potentially harmful dosage.

The best alternatives are unsweetened beverages. Options include plain or sparkling water, infused water with fruit or herbs, and unsweetened hot or iced tea. For those who enjoy the fizz, plain sparkling water is a great substitute. These options offer hydration without artificial ingredients or high acidity.