IntroductionBehavioural changes targeting diet and physical activity to achieve weight loss are considered the cornerstones of metabolic dysfunction-associated steatotic liver disease (MASLD) management. Digital health interventions effectively address barriers in accessing such lifestyle interventions particularly for persons in remote and regional communities that have high rates of MASLD and limited access to healthcare. This research uses co-design methodology to inform the development of a multimodal, digital lifestyle intervention for individuals with MASLD.MethodsOver 20 months (May 2023-January 2025), an iterative co-design process guided by the Double Diamond framework-<i>discover, define, develop, deliver-</i>was implemented. Twenty-seven adults (≥18 years) from Alfred Health, Australia participated in one-on-one interviews to explore insights and perspectives during the <i><u>discover</u></i> phase. This included people with MASLD (<i>n</i> = 10; 50% female; mean age: 63.6 years), and healthcare professionals (<i>n</i> = 17; 59% female; mean age: 37.1 years) [dietitians (<i>n</i> = 5), exercise professionals (<i>n</i> = 6) and hepatologists/clinicians (<i>n</i> = 6)], representing a range of ethnic backgrounds. Key themes were synthesised using a reflexive thematic analysis employing a data-driven, inductive approach during the <i>define</i> phase. The <i>develop</i> phase led to actionable suggestions, and final feedback was sought from participants in the <i>deliver</i> phase.ResultsInterviews identified barriers and facilitators that influenced participant engagement and adherence to the digital intervention, highlighting the need for an evidence-based, personalised and holistic approach during the <i>discover</i> and <i>define</i> phases. Five key themes emerged: i) content relevance and adaptability, ii) personalisation, iii) social and community, iv) barriers and facilitators, and v) website interface design. The <i>develop</i> phase focused on refining the intervention based on participant feedback and <i>deliver</i> phase encompassed finalising the digital intervention.ConclusionsThis iterative co-design process identified the needs and preferences of individuals with MASLD for a multimodal, digital lifestyle intervention. This research will guide a holistic, tailored approach with culturally appropriate resources and community engagement, piloted to assess feasibility.