A large UK-based study found that higher intakes of both diet sodas and non-diet (i.e., sugary) sodas were significantly linked with a higher risk of developing liver disease (specifically MASLD).

In fact, the diet sodas were linked to a higher risk than sugar-laden drinks, even at modest intake levels of a single can per day.

Stick With Water

MASLD (metabolic dysfunction-associated steatotic liver disease) affects a shocking 34% of the U.S. population—and is expected to rise to 41% by 2050—and has become a leading cause of cirrhosis, liver cancer, and liver-related death. 

In the study, researchers followed 123,788 UK Biobank participants without liver disease at baseline for an average of 10.3 years. Beverage consumption was assessed through repeated 24-hour dietary questionnaires using the question: “How many glasses, cans, or cartons containing 8 ounces of diet beverages or sugary beverages did you drink yesterday?”

Participants were then grouped into three intake categories: none, 0.1-1 serving per day, and >1 serving per day.

The findings: consuming more than one serving of diet sodas daily was associated with a 60% higher risk for MASLD and a higher risk for severe liver outcomes, while the same level of sugary sodas was associated with a 50% higher MASLD risk, but NOT to a higher risk of severe liver outcomes.  

Both beverage types were positively associated with higher liver fat content. 

All of this is pretty bad.

Lifestyle modification is key here: Your best bet is to save money and your liver by sticking with boring old water.

Thank you to Medscape and Megan Brooks for their 9/9/2025 online article “Diet Drinks Harder on the Liver Than Sugary Drinks?"