Diet soda does not appear to increase uric acid levels or raise your risk of gout in the way that regular, sugar-sweetened soda clearly does. The largest study on this question, a 12-year prospective cohort of nearly 46,000 men published in the BMJ, found no association between diet soda intake and gout risk, with a trend p-value of 0.99, essentially flat. Even men drinking two or more diet sodas per day had no statistically significant increase in gout compared to those who rarely drank them.
That said, the picture isn’t perfectly clean. A few pieces of evidence suggest diet soda isn’t entirely neutral for metabolic health, and the answer gets more nuanced when you look beyond gout alone.
Why Regular Soda Raises Uric Acid
To understand why diet soda gets a pass, it helps to know what makes regular soda a problem. The culprit is fructose, particularly the high-fructose corn syrup used in most sweetened soft drinks. When your body breaks down fructose, it burns through a molecule called ATP rapidly, and the byproduct of that process is uric acid. A systematic review and meta-analysis of controlled feeding trials confirmed that sugar-sweetened beverages reliably increase blood uric acid levels in both substitution and addition study designs.
Diet sodas swap out fructose for artificial sweeteners like aspartame, sucralose, or acesulfame potassium. Since these sweeteners don’t go through the same metabolic breakdown as fructose, they skip the step that generates excess uric acid. This is the core reason diet soda behaves differently in studies.
What the Largest Gout Study Found
The BMJ cohort study tracked men from 1986 to 1998, recording their dietary habits every four years and documenting new gout diagnoses. After adjusting for age, body weight, kidney function, blood pressure medication use, alcohol intake, meat and seafood consumption, and other dietary factors, diet soft drinks showed no dose-response relationship with gout risk at all. Men who drank one diet soda a day had a relative risk of 1.07 compared to those who drank less than one per month. Men who drank two or more daily had a relative risk of 1.12. Neither figure was statistically significant, and the overall trend was essentially zero.
For comparison, men who drank two or more sugar-sweetened sodas per day had an 85% higher risk of gout in the same study. The contrast is striking and suggests the sweetener itself, not the carbonation or other soda ingredients, drives the relationship with uric acid.
One Survey Found a Different Signal
Not every dataset agrees completely. The American College of Rheumatology’s 2020 gout management guideline noted that in the National Health and Nutrition Examination Survey (NHANES), artificially sweetened carbonated beverage consumption was associated with higher serum uric acid levels. This is a cross-sectional survey, though, meaning it captured a snapshot in time rather than tracking people forward. Cross-sectional data can’t distinguish cause from effect. People who already have high uric acid or gout may switch from regular to diet soda as a health-conscious choice, creating the appearance of an association that runs in the wrong direction.
The ACR guideline conditionally recommends limiting high-fructose corn syrup for gout patients but does not make a specific recommendation against diet soda.
Kidney Health Is a Separate Concern
While diet soda looks neutral for uric acid specifically, heavy consumption has been linked to kidney problems through a different pathway. A study in the Clinical Journal of the American Society of Nephrology found that drinking more than seven glasses of diet soda per week was associated with an 83% higher risk of developing end-stage kidney disease compared to drinking less than one glass per week, even after adjusting for baseline kidney function, diabetes, blood pressure, and serum uric acid.
The proposed mechanism involves phosphorus content rather than sweeteners. Diet sodas, particularly colas, contain phosphoric acid, which increases the acid load your kidneys need to handle. This matters for the uric acid question indirectly: your kidneys are responsible for clearing about two-thirds of the uric acid in your blood. If kidney function declines over time for any reason, your body becomes less efficient at eliminating uric acid, and levels can creep up. So while diet soda may not directly raise uric acid production, very heavy consumption could theoretically impair the organ that removes it.
What Individual Sweeteners Do
Most diet sodas in the U.S. use aspartame, sucralose, acesulfame potassium, or some combination. The evidence on these individual sweeteners is reassuring for uric acid specifically. Repeated daily exposure to sucralose at doses up to 500 mg for 12 weeks showed no effect on uric acid concentrations in healthy people. No published clinical data links acesulfame potassium to changes in uric acid either.
Stevia, which appears in some newer diet beverages, has drawn interest for a different reason. Animal research has found that compounds extracted from stevia residue actually lowered uric acid levels in mice with experimentally induced high uric acid. The extract appeared to both reduce uric acid production and improve intestinal excretion. This is preliminary, mouse-model research, and it used concentrated stevia extracts at doses far beyond what you’d get from a can of soda. Still, it suggests stevia is unlikely to be harmful for uric acid and may eventually prove beneficial.
The Practical Takeaway
If you have gout or elevated uric acid and you’re choosing between regular soda and diet soda, the evidence strongly favors the diet version. Sugar-sweetened beverages are one of the most consistent dietary risk factors for high uric acid and gout flares. Diet soda eliminates the fructose that drives that process. A can or two a day does not appear to meaningfully affect your uric acid levels based on the best available human data.
Where caution is reasonable is at the high end of consumption. Drinking large quantities of diet soda daily has been associated with kidney health risks that could, over the long term, affect your body’s ability to manage uric acid. Water, unsweetened coffee, and low-fat milk are all associated with either neutral or protective effects on uric acid and carry none of the uncertainties that come with heavy diet soda intake.