Diet Soda Shock: New Study Links Daily Can to 60% Higher Liver Disease Risk

A new study has raised fresh concerns about the health effects of both sugary and diet soft drinks. Researchers found that consuming even one can of diet soda a day may raise the risk of developing nonalcoholic fatty liver disease (NAFLD) by nearly 60%. For sugary drinks, the risk increase stood at around 50%.

The findings challenge the long-standing belief that “diet” beverages are a safer alternative. The study, presented at the United European Gastroenterology Week in Berlin, suggests that both types of drinks may have lasting effects on liver health.

Diet Drinks Not as Harmless as Believed

The research was led by Lihe Liu from the First Affiliated Hospital of Soochow University in Suzhou, China. According to Liu, beverages labeled as low- or non-sugar-sweetened (LNSSBs) were associated with a significantly higher risk of metabolic dysfunction-associated steatotic liver disease (MASLD), the updated medical term for NAFLD.

“Even modest intake levels such as a single can per day were linked to increased risk,” Liu said. The study also revealed that people who consumed diet drinks were more likely to die from liver disease than non-consumers. These findings come as MASLD continues to emerge as a growing global health problem.

What the Data Reveals

The study followed nearly 124,000 participants in the UK Biobank who did not have preexisting liver disease. Over a 10-year period, researchers tracked their beverage consumption using 24-hour dietary questionnaires. The analysis showed that both sugary and diet soft drinks contributed to liver fat accumulation and long-term damage.

Interestingly, substituting these drinks with water significantly reduced the risk — by roughly 13% for sugary beverages and 15% for diet versions. Switching between sugary and diet sodas, however, did not offer any benefit.

Sajid Jalil, a clinical associate professor at Stanford University who was not involved in the study, called the research a strong piece of evidence. “This study carries more weight than previous ones because of its large sample size and long follow-up period,” he said. “It clearly shows that both regular and diet soft drinks may harm the liver over time, while water or unsweetened drinks can help protect it.”

Why These Drinks Affect the Liver

Sugary beverages are known to cause spikes in blood sugar and insulin, promoting fat buildup in the liver. Over time, this can lead to inflammation, scarring, and eventually cirrhosis or liver cancer. NAFLD is now one of the leading causes of liver-related deaths worldwide, with nearly 38% of the U.S. population affected.

Diet sodas, though low in calories, may influence liver health through other mechanisms. Liu explained that artificial sweeteners can disrupt gut bacteria, interfere with appetite regulation, and even alter insulin responses. These metabolic shifts may encourage fat storage and impair the liver’s ability to process nutrients efficiently

Water Emerges as the Clear Winner

Replacing either sugary or diet drinks with water provided measurable health benefits in the study. Liu noted that water supports hydration without disturbing metabolism and helps maintain feelings of fullness. “It’s the healthiest default beverage,” she said.

The study’s message is straightforward: neither type of soft drink is harmless. For people who rely on diet sodas to cut sugar intake, the findings suggest that the benefits might not outweigh the risks. Water, herbal teas, and unsweetened beverages remain the best choices for maintaining long-term liver health.

A Growing Health Concern

NAFLD, now known as MASLD, has risen sharply over the past three decades, with a 50% increase in the United States alone. Experts believe that changing dietary habits, sedentary lifestyles, and excessive consumption of processed beverages have contributed to this surge.

The study’s authors hope the findings will prompt further research and lead to clearer public health guidance on artificial sweeteners and their long-term effects. While the results are yet to be peer-reviewed, they add to a growing body of evidence linking diet beverages to metabolic and liver disorders.

The takeaway is clear: whether labeled “sugar-free” or not, sweetened drinks, of any kind, come with risks. The safest switch remains the simplest one: choose water