Background The way in which secondary schools implement and embed the English national school food standards (SFS) has not been fully explored. Normalization Process Theory (NPT) offers a framework for assessing how a way of working becomes embedded as normal practice. We aimed to use NPT to understand school leadership, teacher and caterer perspectives on the implementation of the SFS in secondary schools.

Methods We recruited schools as part of the FUEL study across the Midlands. We asked school senior leaders, governors, teachers and caterers to participate in surveys and one-to-one interviews to explore their views on the implementation of the SFS. Surveys included a set of questions adapted from the Normalisation Measure Development survey instrument, underpinned by NPT. Respondents indicated how much they agreed with a set of statements mapped onto the NPT constructs of coherence, cognitive participation, collective action and reflexive monitoring. Interview guides were developed using NPT to frame question prompts. Survey responses were presented descriptively. Interview transcripts were thematically analysed and mapped onto NPT constructs. Survey and qualitative findings were integrated using a joint display technique.

Results 181 participants from 32 schools completed a survey (52% response) and 21 participants from four schools completed interviews. The SFS were seen to support decision-making around school food, but divergent beliefs on the flexibility of their implementation affected coherent understanding of the SFS, with 52% of survey respondents indicating that they understood what is required of them in relation to SFS implementation. 87% of survey respondents agreed that they would continue to support SFS implementation, but cognitive participation varied depending on job role (78% of caterers viewed the SFS as a legitimate part of their role versus 33% of governors), with qualitative data indicating low levels of oversight by school governor and leadership teams on school food. Barriers to collective action to implement the SFS included a lack of relational work and monitoring, managing competing factors, misinterpretation of the SFS and mistrust in suppliers. Although 87% of survey respondents felt that the SFS were worthwhile, the qualitative data indicated an absence of reflexive monitoring.

Conclusion Challenges in embedding the SFS include perceptions on the flexibility of implementation of the standards, the influence of competing factors, low levels of legitimation beyond those in catering roles and a lack of oversight and monitoring. These findings may help to inform the support and resources offered to schools in implementing the SFS.