Opportunities to improve the school food system in the United Kingdom

Project

Daire, a school-based food and nutrition intervention, and to explore how research evidence and real-world practice can inform improvements in the UK school food system. The following research questions were addressed:<br>(1) What are teachers’ perspectives and practices related to food and nutrition (FN) education and the school food environment in the UK?<br>(2) What is the impact of

Project

Daire on children’s diet diversity, diet quality, and related behaviours, including subgroup differences by gender and deprivation, and which Behaviour Change Techniques (BCTs) were embedded in its interventions?<br>(3) What outcomes and measurement tools have been used in evaluations of SBFNIs?<br><br>Methods<br>A mixed-methods approach was adopted:<br>(1) A cross-sectional survey of UK primary school teachers explored perspectives and practices related to FN education and the school food environment (Chapter 2).<br>(2) A secondary analysis of

Project

Daire, a six-month, cluster-randomized controlled factorial trial conducted across 15 primary schools in areas of socioeconomic disadvantage in Northern Ireland. Schools were assigned to one of four intervention arms: ‘Nourish’, ‘Engage’, ‘Nourish and Engage’ or Control (Delayed). Nourish modified the school food environment, provided exposure to local products and food-related experiences.

Engage delivered interactive, cross-curricular food-related lessons. A total 445 children aged 6-7 years and 458 children aged 10-11 years participated in the study. Outcomes included diet diversity and quality scores (DDS/DQS) and other food- and health-related behaviours, with subgroup analyses by gender and deprivation (Chapter 3).

BCTs were retrospectively mapped to the components of Nourish and Engage interventions, using BCTTv1, and fidelity of delivery was determined (Chapter 4).<br>(3) An umbrella review of systematic reviews of school-based food and nutrition interventions were conducted to explore outcomes used and their measurement tools in the evaluation of these interventions for primary and secondary school children (Chapter 5).<br><br>Results<br>(1) Of 414 teachers participated in the survey, most (93.5%) valued FN education but reported limited classroom time allocation, with a predominant focus on nutrition over food skills and sustainability.

Barriers included inadequate funding, resources, and curriculum time. While digital aids and hands-on activities were commonly used, formal training opportunities were scarce. Facilities such as gardens, cooking facilities and food waste management systems were underutilized for teaching purposes.

Gaps existed in FN policy implementation, and monitoring, with many teachers unsure of policy presence, particularly in areas such as food sustainability, fundraising, and external monitoring. Despite challenges, most teachers expressed a strong interest in training and FN integration within the curriculum.<br>(2) The Nourish intervention increased school (adjusted mean difference= 2.79, 95% CI: 1.44, 4.14; P<0.001) and total DDS among 10–11-year-olds (adjusted mean difference= 1.55, 95% CI: 0.65, 2.44; P=0.001).

However, no significant changes were observed in home DDS, in younger children or diet quality across age groups. The Engage intervention showed no significant impact on DDS or DQS. Subgroup analyses indicated greater improvements in school DQS (adjusted mean difference= 2.4, 95% CI 0.31, 4.4; P=0.02) and total DQS (adjusted mean difference=1.8, 95% CI 0.19, 3.4; P=0.03) among older children from deprived areas.

Baseline food or health-related behaviours were generally positive, with no significant follow-up changes in either age group who received Nourish or Engage. Retrospective mapping identified 12 distinct BCTs across components of each intervention, with fidelity of delivery at 60.65% for Nourish and 53% for Engage.<br>(3) Ninety-seven systematic reviews, encompassing 965 primary studies, were included. These studies reported a diverse range of outcomes across four key domains: diet (68.8%), physical health (44.8%), social and emotional well-being and behaviour (9.2%), and education (6.4%), utilizing various assessment tools.

The findings emphasize the urgent need for a standardized core outcome set (COS) to enhance comparability across studies, facilitating improved evidence synthesis and the translation of research into policy and practice.<br><br>Discussion and Conclusion<br>Findings from

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Daire highlighted the potential of a whole-school, environment-focused strategies, with Nourish improving dietary diversity and Total Difficulties Score, particularly in 6 disadvantaged school areas. However, limited effects on diet quality, the home environment, and younger children underscore the need for refinement. The limited effectiveness of Engage reflected the challenges of teacher-led delivery under curriculum pressures and the importance of complementing education with supportive environmental modifications.

Mapping of BCTs revealed misalignments between strategies and intended outcomes, emphasising the value of embedding explicit theoretical frameworks and aligning with the Health Promoting Schools’ whole-school approach. Greater parental involvement and longer intervention duration are also needed to extend and sustain change beyond the school setting. At a broader level, systemic barriers, including curriculum pressures, limited teacher training, and insufficient resources, constrained the delivery of FN.

Addressing these requires stronger leadership engagement, targeted investment in professional development, and closer alignment of health and education agendas. The umbrella review further highlighted the absence of standardised outcome measures across SBFNIs, reinforcing the need for a COS to enable robust evaluation, comparability across interventions, and long-term monitoring of school food policies and practices. The findings presented here constitute a first step toward establishing such a framework.<br><br>Taken together, expanding initiatives such as

Project

Daire, in tandem with policy integration, improved monitoring mechanisms, and alignment with WSA, could promote a healthier and more equitable school food system and reduce dietary inequalities and support children’s health, well-being, and educational outcomes.