Previous studies indicate a link between non-alcoholic fatty liver disease (NAFLD) and unhealthy dietary patterns or nutrient intake. However, it remains unclear whether ultra-processed foods (UPF) contribute to an increased risk of NAFLD. This study aimed to explore how ultra-processed food consumption correlates with severe NAFLD using the UK Biobank data.

This prospective cohort study included 143,073 participants from the UK Biobank. UPF consumption levels were determined using the NOVA classification and quantified from 24-h dietary recall data. The association between UPF consumption and severe NAFLD (hospitalization or death) was initially examined using Cox proportional hazards models with intake quartiles. Nonlinear associations were investigated using penalized cubic splines fitted in the Cox proportional hazards models. Adjustments were made for general characteristics, sociodemographic factors, body mass index (BMI), and lifestyle.

Throughout the median follow-up period of 10.5 years, 1,445 participants developed severe NAFLD. The adjusted models indicated a significant increase in severe NAFLD risk in higher UPF intake groups compared to the lowest quartile (HR: 1.26 [95% CI: 1.11–1.43]). Subgroup analysis revealed that individuals with a BMI of 25 or higher were at greater risk in the highest quartile of UPF consumption. Sensitivity analyses yielded results consistent with these findings.

Higher consumption of UPF is associated with an increased risk of severe NAFLD. Reducing the intake of UPF can be a potential approach to lower the risk of NAFLD.