Background The objective of this study was to evaluate the acceptance of an employer-led free lunch initiative and its effect on health, diet, and attitudes towards health and diet amongst employees in a small workplace in Northern Ireland. Methods This was a controlled, employer-led pilot intervention, which was evaluated through a mixed methods approach. Results Seventeen participants from the intervention site and 14 participants from the control site completed all assessments. Post-intervention, there was no difference in change in dietary measures between the sites, except for saturated fat intake during weekdays (IS: − 1.3% of calories, SD: 4.3; CS: 2.8% of calories, SD: 6.6; P-value < 0.05). Qualitative information was summarised to highlight employees’ expectations and experiences with the intervention. Conclusion This study highlights the challenges that need to be considered when implementing a free lunch initiative for staff.