Evaluating and comparing the healthy food and physical activity environment in schools in Sri Lanka and New Zealand : a study among 5- to 13-year-old children : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Science, Massey University, Albany, New Zealand

Abstract

Background Schools are critical environments for shaping children’s physical activity (PA) and dietary behaviours, yet comparative evidence across diverse national contexts remains scarce. This thesis addresses this gap by evaluating and comparing school PA behaviours, food environments, and dietary adequacy among children aged 5–13 years in Sri Lanka (SL) and New Zealand (NZ), two countries with contrasting socio-economic contexts, cultural norms, and school health policies. This comparison provides insights into how diverse environments influence children’s health behaviours and identifies opportunities for context-specific interventions. The research also advances methodological approaches for PA measurement and dietary assessment in paediatric populations. While the study provides valuable cross-country insights, it is based on a convenience sample of schools and should be considered exploratory rather than nationally representative. Objectives The research aimed to: (1) synthesise evidence on accelerometer-based PA measurement in Asian children and identify methodological gaps; (2) compare objectively measured PA and children’s subjective experiences of physical education in SL and NZ; (3) examine school food environments, including food policy and physical food availability, across both countries; (4) develop and validate a modified 24-hour multiple-pass dietary recall (24-MPR) protocol tailored for NZ children; and assess and compare energy and key nutrient intake adequacy among schoolchildren aged 9–13 years in both contexts. Methods This thesis comprises a narrative review, two cross-country pilot studies, a validation study, and an exploratory dietary adequacy analysis. Data collection included accelerometer-based PA measurement, child-reported experiences, and school food environment assessment using structured questionnaires completed by school staff and food suppliers. Dietary intake was assessed using a modified 24-MPR protocol validated against weighed food records. Nutrient adequacy was evaluated using national nutritional reference values, including Estimated Average Requirements (EAR), Adequate Intake (AI), and Acceptable Macronutrient Distribution Ranges (AMDR) applied separately to both country-specific recommendations. Statistical analyses included descriptive statistics and comparative tests (e.g., t-tests and chisquare tests) to examine differences across countries, genders, and other relevant variables. Significance was set at p < 0.05. Analyses were performed using R software for descriptive and inferential statistics, while validity and reliability metrics were calculated using Hopkins’ spreadsheets. Results The accelerometry review revealed limited validation studies and context-specific cut points for Asian children, highlighting the need for culturally tailored calibration protocols. The PA comparison demonstrated significant differences in objectively measured activity levels and subjective experiences, with gender and cultural factors influencing engagement and motivation. Valid accelerometer data were obtained from 464 children in NZ and 124 in SL. New Zealand children recorded more steps overall (992 vs 873 steps per hour; p < 0.01) and on weekdays (1034 vs 867; p < 0.01), while SL children achieved higher moderate-to-vigorous physical activity (MVPA) (11 vs 7 min per hour; p < 0.001). Sedentary time was greater in NZ (34 vs 31 min per hour; p < 0.001), and light activity was marginally higher in NZ (19 vs 18iii min per hour; p < 0.001). Younger children (5–8 years) accumulated more steps than older peers (p < 0.001), and boys were consistently more active than girls in both countries (p < 0.001). School food environment assessments revealed that 87% of the SL schools in the sample of 30 had a canteen, while 64% of the NZ schools in the policy and practices survey sample of 75 reported having a written food policy. Comparative analyses of Chi-square revealed a significant difference in access to food and drinks for school activities between NZ and SL schools (χ² = 16.39, p < 0.001), while other factors such as water fountain availability and promotion of healthy eating did not differ significantly. However, only 28% of these NZ schools had updated their policy within the past two years, and compliance with the national School Canteen Policy in SL was weak, with only one school reporting regular committee meetings. Canteens in the SL schools frequently sold deep-fried foods, confectionery, and sweetened beverages, whereas packaged snacks and sweet baked goods dominated the menus of these NZ schools. Validation of the modified 24-MPR in NZ showed minimal mean bias for energy (−0.2%) and moderate validity for macronutrients (r = 0.43–0.63), while micronutrients were more variable (r = 0.10–0.42). Reliability was small for macronutrients (ICC = 0.30) and moderate for calcium (ICC = 0.56), supporting its use for group-level dietary assessment. Nutrient adequacy analysis indicated widespread inadequacies in SL, where more than 90% of children had insufficient fibre and calcium, and energy inadequacy exceeded 87% in younger and 97% in older age groups. In NZ, energy and protein intakes were adequate, but inadequacies were common for fibre (42–45%), calcium (42–50%), and vitamin A (80–92%) among children. Conclusions This research demonstrates the feasibility and value of integrated, school-based strategies that combine objective PA monitoring, child-centred perspectives, enforceable food policies, and validated dietary assessment tools. In spite of differences in policy framework, both countries have similar gaps between policy intention and implementation. They consequently cause such wide-ranging exposure to unhealthy food environments for school-aged children. Findings inform policy and practice by emphasising culturally appropriate PA promotion, mandatory healthy canteen standards, and investment in school meal programmes to address nutritional gaps. Methodological contributions include considerations of accelerometry in SL contexts and a validated child-friendly dietary recall protocol. Future research should focus on larger, nationally representative samples to validate these findings and strengthen generalisability.