Diet Soda May Raise Your Liver Disease Risk

Many people turn to diet soda because it is 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 the risk of serious liver disease.

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

With this in mind, it is more important than ever to understand risk factors, including our drinking habits. To expand our knowledge about beverages and the risk of liver disease, researchers presented these findings 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 tracked more than 100,000 participants who had no signs of liver disease at the start of the study.

Over an average period of 10.3 years, these participants provided detailed information about their diet, including their consumption of both sugar-sweetened beverages (SSBs) such as regular sodas and low-sugar or unsweetened beverages (LNSSBs) such as diet sodas. Researchers used this information to find out who developed MASLD and who had other liver-related health problems.

The study was designed to be thorough. By following a large group of people over a decade, scientists were able to observe how drinking habits over time are linked to the risk of developing liver disease. They also used advanced imaging techniques to measure the actual fat content in some participants’ livers, 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 associated with a higher risk of developing MASLD.

Specifically, people who consumed more than about one can (over 250g) of diet or regular soda per day had an increased risk of developing MASLD compared to people who drank that can 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 found that diet drinks are not the “safer” option when it comes to liver health. In fact, their consumption was also associated with a higher risk of dying from liver-related causes, an association not seen with sugary drinks in this particular study. Both types of drinks were also directly linked to higher levels of fat accumulation in the liver.

Lihe Liu, the study’s lead author, explained the possible reasons for these results. Sugary drinks can cause rapid spikes in blood sugar and insulin, which promotes weight gain and contributes to liver fat formation. Although diet drinks are sugar-free, they can affect your health in other ways. They can alter the gut microbiome, impair satiety, and even create sweet cravings that lead to unhealthier eating habits.

While this study provides important insight into the connection between sugar and diet soda consumption and the risk of liver disease, it is important to keep some limitations in mind. First, the research relied on self-reported dietary information, which can sometimes be inaccurate due to participants’ memory lapses or unintentional misstatements. This means that actual beverage intake may differ from what is recorded.

Furthermore, the study was observational in nature. This type of research can reveal connections between behaviors and health outcomes, but it cannot definitively prove that diet or sugary soda consumption causes liver disease. Other factors not fully captured in the study, such as lifestyle choices or genetics, may also play a role.

When defining diet sodas, researchers did not specify which sweetener was used as an ingredient. Because some data suggests that certain non-nutritive sweeteners (such as sucralose) were not significantly broken down in the gut and did not cause major changes in the microbial environment, different diet sodas made with different sweeteners may have different effects on liver health.

Finally, further research is needed to fully understand the underlying biological mechanisms and confirm these results. Future studies, including long-term randomized controlled trials, will help clarify whether eliminating sweetened sodas from the diet directly reduces the risk of liver disease or whether other factors play a role.

How does this translate to real life?

The conclusions of this study offer clear and practical advice for everyday life. The general perception of diet sodas as a healthy alternative may not be a wise assumption, especially if you’re already concerned about your liver health.

The key takeaway is to limit your intake of all Sweetened drinks – whether artificially sweetened or sweetened with sugar – may be the best solution for your liver. Based on these observational data, the study concluded that replacing a can of sugary soda or diet soda with a glass of water each day significantly reduced the risk of developing MASLD:

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

However, simply switching from regular soda to diet soda did not reduce risk. This suggests that the problem lies with the sweet drinks themselves and not just the sugar content. However, until more definitive data is available, we cannot definitively say that diet soda consumption causes liver health problems.

If you want to drink less diet sodas, that doesn’t mean you have to limit yourself entirely to water. You can also opt for sparkling water with a splash of juice, drink iced green tea, or enjoy an unsweetened carbonated drink like a La Croix.

Our expert opinion

This comprehensive study, presented 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 problem, making informed decisions about what we drink could be an important step toward prevention.

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