Evidence of epigenetic risk of metabolic syndrome (MetS) from both parents, and its increasing prevalence globally, underscores the necessity for effective lifestyle interventions preconception. Despite this, very few studies have examined couples-based interventions and those which are concerned with foetal health rarely monitor paternal health outcomes(1). This study evaluates the feasibility and adherence of a 10-week couples-based lifestyle intervention targeting diet and physical activity. Utilising an exploratory sequential mixed methods design, the study recruited 16 participants (8 couples) aged 18–44 years, living together with a BMI between 18.5 and 38 kg/m². Participants received personalised dietary and physical activity guidance aligned with national guidelines, with progress tracked via the Easy Diet Diary app and the International Physical Activity Questionnaire (IPAQ). Quantitative data were collected at baseline, mid-point, and end of the intervention, while qualitative insights were obtained through semi-structured interviews post-intervention. The intervention aimed to leverage the natural support system within couples to enhance adherence to healthy lifestyle behaviours. Quantitative findings indicated positive trends in reducing sedentary behaviour by an average of 1105 minutes per week and increasing vegetable consumption by 1.7 servings per day. Participants also showed improvements in BMI and waist-to-hip ratios, with significant reductions noted by the end of the intervention. Qualitative data and thematic analysis provided rich context to these findings and underscored the importance of mutual support, shared responsibility, and accountability in fostering adherence, but also indicated a need for more flexible and user-friendly tracking tools. Partner encouragement, joint activities such as meal planning, exercising together, and shared responsibility emerged as significant adherence enhancers while differing timing and work schedules were a common barrier. This study demonstrates that a couples-based approach can effectively enhance adherence to lifestyle modifications, promoting significant behavioural changes and improving health outcomes by leveraging the inherent support system within the relationship, thereby facilitating more sustainable health behaviours. Future research should explore long-term impacts and optimise intervention strategies to address identified challenges, ensuring broader applicability and effectiveness in diverse populations. The promising results of this feasibility study advocate for the potential scalability of couples-based interventions as a public health strategy to combat MetS and related conditions.