Diet Soda May Raise Your Liver Disease Risk

Many people reach for a diet soda as a healthier choice, especially when compared to a regular, sugary drink. However, a new study suggests that both artificially sweetened drinks and their sugary counterparts could significantly increase your risk of developing a serious liver condition.

The condition in question is metabolic dysfunction-associated steatotic liver disease, or MASLD. Formerly known as non-alcoholic fatty liver disease (NAFLD), MASLD occurs when excess fat builds up in the liver. Over time, this can lead to inflammation, scarring, and severe liver damage. It has become the most common chronic liver disease globally, affecting an estimated 30% of adults in certain countries and is a growing cause of liver-related deaths.

With this in mind, understanding the risk factors, including what we drink, is more important than ever. To help add to what we know about beverages and liver disease risk, researchers shared these results at the United European Gastroenterology (UEG) Week 2025 medical conference. Let’s unpack what they presented.

How Was the Study Conducted?

To investigate the link between sweetened drinks and liver disease, researchers conducted a large-scale, long-term study using data from the UK Biobank, a massive health resource. They followed more than 100,000 participants who had no signs of liver disease at the beginning of the study.

Over a median period of 10.3 years, these participants provided detailed information about their diets, including their consumption of both sugar-sweetened beverages (SSBs) like regular sodas and low- or non-sugar-sweetened beverages (LNSSBs), such as diet sodas. Researchers used this information to track who developed MASLD and who experienced other liver-related health issues.

The study was designed to be thorough. By following a large group of people for over a decade, scientists could observe how beverage habits were associated with the risk of developing liver disease over time. They also used advanced imaging techniques to measure the actual fat content in the livers of some participants, adding another layer of concrete evidence to their findings.

What Did the Study Find?

The study found that regular consumption of both types of drinks were linked to a greater risk of developing MASLD.

Specifically, individuals who consumed more than about one can (over 250g) per day of either diet or regular soda had an increased risk of being diagnosed with MASLD compared to those who drank them less frequently.

• Diet Drinks (LNSSBs): Higher intake was associated with a 60% increased risk of developing MASLD.
• Sugary Drinks (SSBs): Higher intake was associated with a 50% increased risk of developing MASLD.

Interestingly, the study revealed that diet drinks were not the “safer” option when it comes to liver health. In fact, their consumption was also linked to a higher risk of death from liver-related causes, an association not seen with sugary drinks in this particular study. Both beverage types were also directly linked to higher levels of fat accumulation in the liver.

Lihe Liu, the lead author of the study, explained the potential reasons behind these findings. Sugary drinks can cause rapid spikes in blood sugar and insulin, which promotes weight gain and contributes to liver fat. Diet drinks, while free of sugar, may disrupt health in other ways. They may alter the gut microbiome, interfere with feelings of fullness, and even stimulate a sweet craving that encourages unhealthier eating habits. 

While this study provides important insights into the relationship between both sugary and diet soda consumption and liver disease risk, it’s important to keep a few limitations in mind. First, the research relied on self-reported dietary information, which can sometimes be inaccurate due to memory lapses or unintentional misreporting by participants. This means actual beverage intake might differ from what was recorded.

Additionally, the study was observational in nature. This type of research can uncover associations between behaviors and health outcomes, but it cannot definitively prove that drinking diet or sugary sodas causes liver disease. Other factors not fully captured in the study, such as lifestyle choices or genetic predispositions, might also play a role.

When defining diet sodas, the researchers did not indicate which sweetener was used as an ingredient. Since some data suggests that certain non nutritive sweeteners (like sucralose) were not significantly broken down in the gut and didn’t cause major changes to the microbial environment, different diet sodas made with different sweeteners may have a different impact on liver health.

Lastly, more research is needed to fully understand the underlying biological mechanisms and to confirm these results. Future studies, including long-term randomized controlled trials, will help clarify whether removing sweetened sodas from the diet directly reduces liver disease risk or if other factors are at play.

How Does This Apply to Real Life?

The conclusions from this study offer clear and practical advice for daily life. The common perception of diet sodas as a healthy alternative might not be a wise presumption, especially if you’re concerned about your liver health already.

The key takeaway is that limiting your intake of all sweetened beverages—whether artificially sweetened or sweetened with sugar—may be the best approach for your liver. Based on this observational data, the study found that substituting one can of either a sugary or diet soda with a glass of water each day significantly reduced the risk of developing MASLD:

• Replacing a sugary drink with water lowered the risk by about 13%.
• Replacing a diet drink with water lowered the risk by about 15%.

Simply switching from regular soda to diet soda, however, offered no reduction in risk. This suggests that the problem lies with the sweet drinks themselves, not just the sugar content. However, until stronger data is available, we can not definitively say that drinking diet soda will cause liver health concerns.

If you’d like to start drinking fewer diet sodas, that doesn’t mean you have to stick to water entirely. You might also consider opting for sparkling water with a splash of juice, having iced green tea or enjoying an unsweetened carbonated drink, like a La Croix.

Our Expert Take

This comprehensive study shared at the United European Gastroenterology (UEG) Week 2025 medical conference provides evidence that both sugary and artificially sweetened drinks may pose a risk to your liver health. As metabolic dysfunction-associated steatotic liver disease (MASLD) becomes an increasingly widespread global health issue, making informed choices about what we drink could be a powerful step toward prevention.

While sugary drinks have been under scrutiny for years, this research places diet drinks in the same category of concern. By cutting back on both regular and diet sodas and opting for water or other unsweetened drinks, you may actively reduce your risk of developing liver disease and support your overall metabolic health.