Diet drinks may not be “healthier” than sugary drinks when it comes to liver health.
A large UK Biobank study found that higher intakes of both sugar-sweetened beverages (SSBs) and low- and non-SSBs (LNSSBs) were significantly associated with a higher risk of developing metabolic dysfunction-associated steatotic liver disease (MASLD).
In fact, low- or artificially sweetened beverages were actually linked to a higher risk for MASLD than sugar-laden drinks, even at modest intake levels such as a single can per day.
“These findings challenge the common perception that these drinks are harmless and highlight the need to reconsider their role in diet and liver health, especially as MASLD emerges as a global health concern,” lead author Lihe Liu, a graduate student in the Department of Gastroenterology at The First Affiliated Hospital of Soochow University in Suzhou, China, said in a news release.
She presented her research at the United European Gastroenterology (UEG) Week 2025 in Berlin, Germany.
Stick With Water
MASLD affects 38% of the global population and has become a leading cause of cirrhosis, liver cancer, and liver-related death. Lifestyle modification remains “a cornerstone” of MASLD management. Current guidelines advise against SSBs, but the evidence regarding LNSSBs remains “limited,” Liu explained in her presentation.
To investigate, the researchers analyzed data of 123,788 UK Biobank participants without liver disease at baseline who were followed 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 250 mL (roughly 250 g) of SSBs or LNSSBs did you drink yesterday?”
Intake was averaged across at least two recalls, and participants were grouped into three intake categories: none, more than 0 to one serving per day, or more than one serving per day.
The primary outcome was incident MASLD, and secondary outcomes included liver-related mortality and liver fat content measured using MRI-derived proton density fat fraction.
In the fully adjusted multivariable Cox model, compared with no consumption, consuming more than one serving of LNSSBs daily was associated with a 60% higher risk for MASLD (hazard ratio [HR], 1.599). The level of consumption of SSBs was associated with a 50% higher risk (HR, 1.469).
Consuming more than one serving of LNSSBs daily was also associated with a higher risk for severe liver outcomes (HR, 1.555), while SSBs showed no significant association after adjustment.
Neither SSBs nor LNSSBs showed significant associations with all-cause mortality in fully adjusted models.
Substituting either beverage with water reduced the risk for MASLD by 12.8% for SSBs and 15.2% for LNSSBs, Liu reported.
Both beverage types were positively associated with higher liver fat content. Consumption of more than one serving of SSBs and LNSSBs daily was associated with about 5% and 7% higher liver fat levels, respectively, than nonconsumption.
“The higher sugar content in SSBs can cause rapid spikes in blood glucose and insulin, promote weight gain, and increase uric acid levels, all of which contribute to liver fat accumulation. LNSSBs, on the other hand, may affect liver health by altering the gut microbiome, disrupting the feeling of fullness, driving sweet cravings, and even stimulating insulin secretion,” Liu said.
“The safest approach is to limit both sugar-sweetened and artificially sweetened drinks. Water remains the best choice as it removes the metabolic burden and prevents fat accumulation in the liver, whilst hydrating the body,” she concluded.
Reached for comment, Sujit V. Janardhan, MD, PhD, director of the steatotic liver disease program, Rush University Medical Center, Chicago, said the findings “certainly should cause one to take pause from the popular notion that diet or non-sugar-sweetened beverages are healthier than their sugar-sweetened alternatives.
He cautioned, however, that it would be “important to confirm cofounders are adequately addressed in this large population-based study.”
“We must better understand what other exposure and characteristics were present in patients who had increased intake of non-sugar-sweetened beverages,” Janardhan told Medscape Medical News.
“For example, it’s possible people who drank more non-sugar-sweetened beverages had more cardiovascular or metabolic risk factors (which prompted them to switch to the ‘diet’ alternative) and that it is these comorbidities that drove an association with increased MASLD incidence and liver-related mortality,” Janardhan noted.
“If there is one finding that seems easy to take away from this study, it’s that people who drank more water in place of sweetened beverages had reduced risk of MASLD,” he told Medscape Medical News.