A major new study presented at UEG Week 2025 has found that both sugar-sweetened beverages (SSBs) and low- or non-sugar-sweetened beverages (LNSSBs) are linked to a significantly higher risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD).
The research followed 123,788 participants from the UK Biobank who had no existing liver disease at the start of the study. Beverage consumption was assessed through repeated 24-hour dietary questionnaires. Researchers then examined the association between SSB and LNSSB intake and the development of MASLD, liver fat accumulation, and liver-related deaths.
Higher Beverage Intake, Higher Liver Disease Risk
The findings revealed that consuming more than 250 grams per day of either SSBs or LNSSBs increased the risk of developing MASLD by 50% and 60%, respectively. Over a median follow-up period of 10.3 years, 1,178 participants developed MASLD, and 108 died from liver-related causes.
While both beverage types were linked to higher liver fat content, LNSSBs — often marketed as “healthier” alternatives — were additionally associated with an increased risk of liver-related mortality. This surprising result challenges the popular belief that sugar-free drinks are a safe substitute for sugary beverages.
What Is MASLD and Why It Matters
MASLD, previously known as non-alcoholic fatty liver disease (NAFLD), occurs when excess fat builds up in the liver. Over time, this accumulation can trigger inflammation (hepatitis), leading to fatigue, pain, and appetite loss.
The disease has rapidly become one of the most common chronic liver conditions worldwide, now affecting over 30% of the global population. Experts warn that it is a growing cause of liver-related deaths, with cases expected to rise alongside global obesity and diabetes rates.
Artificial Sweeteners Under the Microscope
Lead author Lihe Liu explained that the study shows how both sugary and artificially sweetened beverages may harm liver health.
“SSBs have long been under scrutiny, while their ‘diet’ alternatives are often seen as the healthier choice,” Liu said. “However, both are widely consumed, and their effects on liver health have not been well understood.”
The study found that even modest LNSSB intake — such as a single can per day — was linked to a significantly higher risk. It was connected particularly to the risk of MASLD. “These findings challenge the perception that diet drinks are harmless. They highlight the need to reconsider their role in nutrition and liver health,” Liu added.
How Sugary and Diet Drinks Harm the Liver
The researchers also discussed the biological mechanisms behind these associations. High sugar intake from SSBs can cause rapid spikes in blood glucose and insulin. It can also promote weight gain. Additionally, it can elevate uric acid levels. All of these factors contribute to liver fat buildup.
In contrast, LNSSBs may disrupt the gut microbiome, interfere with satiety signals, and increase sweet cravings. Some artificial sweeteners might even stimulate insulin secretion, mimicking the effects of sugar on metabolism.
These processes can collectively overload the liver. This leads to fat accumulation. It also increases the risk of metabolic and inflammatory liver conditions.
Water: The Healthiest Replacement
Importantly, the study found that replacing either SSBs or LNSSBs with water substantially lowered the risk of MASLD. Substituting sugary drinks with water reduced risk by 12.8%, while replacing diet drinks with water cut risk by 15.2%. However, switching between SSBs and LNSSBs did not provide any meaningful health benefit.
“The safest approach is to limit both sugar-sweetened and artificially sweetened drinks,” Liu emphasized. “Water remains the best choice as it removes the metabolic burden and prevents fat accumulation in the liver while hydrating the body.”
Implications for Global Health
The findings carry significant implications for public health, especially as beverage companies continue to market low- and no-sugar products as healthier choices. Experts suggest that both types of drinks may contribute to a broader metabolic crisis, including cardiovascular, renal, and liver diseases.
As global consumption of diet beverages rises, public health authorities may need to update dietary guidelines and labeling standards to reflect these new risks. Policymakers are also urged to promote water consumption and healthier beverage alternatives as part of national nutrition strategies.
Next Steps in Research
The study authors plan to explore the causal mechanisms in greater depth through long-term randomized trials and genetic studies. Future research will focus on how sugar and its substitutes interact with the gut microbiome and how these interactions influence liver fat metabolism and disease development.
“Our findings are an important step toward understanding the complex relationship between sweetened drinks and liver health,” Liu concluded. “Further investigation will help clarify how even low-calorie sweeteners may disrupt metabolic balance and contribute to chronic disease.”
Takeaway
Whether sweetened with sugar or artificial substitutes, frequent consumption of these beverages may put liver health at serious risk. As MASLD emerges as a global epidemic, experts agree that moderation — and a return to water — is the safest and most effective choice for long-term health.
