Highlights
The NAPSACC UK trial, a multicentre cluster-randomised controlled trial, investigated the effectiveness of an environmental intervention on nutrition and physical activity in Early Childhood Education and Care (ECEC) settings. Key highlights include:
- No significant difference was observed in the co-primary outcomes: total energy consumed per eating occasion (p = 0.09) and total physical activity (p = 0.64).
- Secondary outcomes revealed a significant reduction in energy served and consumed specifically during lunch (approx. -68 kcal, p = 0.009).
- Implementation fidelity was lower than intended, likely due to substantial staffing pressures and systemic challenges within the ECEC sector.
- The findings suggest that individual childcare setting interventions may be insufficient, pointing toward the necessity of policy-level and statutory changes.
Background: The Critical Role of ECEC in Early Development
The prevalence of childhood obesity remains a significant global health challenge, with early childhood representing a critical window for establishing lifelong health behaviors. Early Childhood Education and Care (ECEC) providers are pivotal in this landscape, as a vast majority of children aged 2 to 5 spend a significant portion of their waking hours in these environments. In the United Kingdom, as in many developed nations, ECEC settings are seen as ideal venues for public health interventions aimed at improving nutrition and physical activity.
The Nutrition and Physical Activity Self-Assessment for Child Care (NAPSACC) intervention was originally developed in the United States, where it showed promise in improving childcare environments. However, cultural and systemic differences necessitated a UK-specific adaptation. The NAPSACC UK intervention was designed to modify ECEC policies and practices through staff workshops, self-assessment tools, and targeted assistance over a one-year period. The goal was to reduce excessive energy consumption and increase physical activity among young children, thereby mitigating the risk of early-onset obesity.
Study Design and Methodology
The NAPSACC UK trial was a repeated cross-sectional, multicentre, two-arm, single-blind, parallel-group, cluster-randomised controlled trial. The study enrolled 52 ECEC providers across the UK, which were randomised into either the intervention group (n=25) or the control group (n=27). A total of 835 children aged 2-5 years participated in the study.
Randomisation and Blinding
To ensure rigorous methodology, randomisation was conducted by a statistician blinded to the identity of the ECEC providers. Allocation was stratified by local authority area and Index of Multiple Deprivation (IMD) scores to ensure balanced representation across socioeconomic backgrounds. While participants could not be blinded to their allocation, the senior statistician and the majority of the research team remained blinded throughout the analysis phase.
Endpoints and Measurement
The trial utilized two co-primary outcomes measured 12 months post-baseline:
- The average total energy consumed per eating occasion (lunch or snack) within the ECEC setting.
- Total physical activity on ECEC days, assessed via accelerometry.
Secondary outcomes included moderate-to-vigorous physical activity (MVPA), sedentary time, energy served at lunch, diet quality, and Body Mass Index (BMI) z-scores. Data collection relied on high-quality objective measures, including energy intake tracking and 12-month follow-up assessments.
Key Findings: Analyzing the Evidence
The trial results presented a complex picture of the intervention’s impact. Analysis was conducted on an intention-to-treat basis, reflecting real-world application of the program.
Primary Outcomes: A Null Result
After 12 months, the study found no evidence of a statistically significant difference between the intervention and control groups regarding the primary outcomes. The adjusted geometric mean ratio for energy consumed per eating occasion was 0.86 (95% CI 0.72-1.03; p = 0.09). Similarly, total physical activity showed an adjusted mean difference of -2.13 minutes (95% CI -10.96 to 6.70; p = 0.64). These results indicate that the NAPSACC UK intervention, as implemented, did not achieve its primary objectives of reducing caloric intake or increasing physical movement.
Secondary Outcomes: Specific Nutritional Shifts
Despite the null primary results, certain secondary outcomes showed improvement. The intervention group demonstrated significantly lower lunch energy served (adjusted mean difference -69.1 kcal; p = 0.004) and consumed (adjusted mean difference -67.7 kcal; p = 0.009). These findings suggest that while the overall daily energy intake did not change significantly, specific mealtime practices were influenced by the intervention. However, no significant differences were found in MVPA, sedentary time, diet quality, or BMI z-scores.
Expert Commentary: Implementation Barriers and Policy Directions
The failure of NAPSACC UK to meet its primary endpoints warrants a deep dive into the implementation context. The researchers noted that intervention fidelity—the degree to which the program was delivered as intended—was lower than anticipated. This was largely attributed to the immense staffing pressures currently facing the UK childcare sector. When ECEC providers are under-resourced and over-stretched, implementing comprehensive environmental changes becomes secondary to basic care and operational survival.
The Limits of ‘High Agency’ Interventions
The results underscore a growing consensus in public health: ‘high agency’ interventions—those that require significant effort, time, and decision-making by individuals or specific settings—often struggle to produce sustainable results in environments under stress. In contrast, ‘low agency’ changes, such as statutory regulations on food standards or mandatory physical activity requirements, may provide more equitable and robust outcomes.
Comparison with US Data
While previous iterations of NAPSACC in the US showed more positive results, the UK trial highlights the importance of local context. Differences in childcare funding, regulatory oversight, and baseline nutrition standards mean that a successful model in one country cannot be seamlessly transplanted to another without considering the structural constraints of the host system.
Conclusion: Moving Beyond the Individual Setting
The NAPSACC UK trial provides high-quality evidence that environmental interventions focusing on staff training and self-assessment may not be sufficient to drive meaningful changes in child health outcomes within the current ECEC framework. While the reduction in lunch-time energy intake is a positive secondary finding, it does not compensate for the lack of change in total daily energy or physical activity.
For clinicians and policymakers, the takeaway is clear: future efforts should prioritize policy-level and statutory changes. By embedding nutrition and physical activity requirements into the legal and regulatory fabric of early childhood education, we can reduce the burden on individual providers and create a more consistently healthy environment for all children, regardless of the specific setting they attend.
Funding and Trial Registration
This study was funded by the National Institute for Health and Care Research (NIHR) Public Health Research Programme (Project: 127551). The trial is registered under ISRCTN33134697.
References
- Kipping R, et al. Effectiveness of an environmental nutrition and physical activity intervention in early childhood education and care settings (NAPSACC UK): a multicentre cluster randomised controlled trial. Lancet Reg Health Eur. 2025;61:101550.
- Ward DS, et al. Nutrition and Physical Activity Self-Assessment for Child Care (NAP SACC): innovative strategies for promoting healthy eating and physical activity. Methods. 2008;45(3):181-186.
- Public Health England. Childhood Obesity: A Plan for Action. 2017.
