The effect of student age on plate waste in Latvian primary and lower secondary school settings

Overview

This pilot study examined plate waste across four primary and lower secondary schools in Rezekne, Latvia, to assess how student age influences food waste generation in school catering contexts. The research was conducted within a pre-served catering model where fixed portions and unified menus were standardised across all participating institutions. The investigation surveyed 17,144 plates across three measurement periods during the 2023/2024 academic year, focusing on filtered plate waste comprising staples and protein dishes while excluding inconsistently served items.

Methods and approach

A two-way ANOVA design was employed to evaluate the effects of student age group (primary: grades 1–4, aged 7–10; lower secondary: grades 5–7, aged 11–13) and measurement period on plate waste generation. All four schools operated under identical catering conditions featuring fixed portion sizes with no student choice of dishes or portion magnitudes. A standardised menu was implemented across all schools and repeated during each data collection interval to ensure methodological consistency and comparability across institutions and time periods.

Results

The analysis demonstrated a statistically significant age effect on filtered plate waste, with younger primary students producing greater average plate waste than older lower secondary students. No significant main effect for measurement period or age-by-period interaction was detected, indicating consistent age-related plate waste patterns across the three data collection intervals. School-level variation was observed, with younger students generating significantly higher plate waste in schools S1–S3 relative to older students, whereas this differential was not significant in S4, attributed to a narrower waste gap between age groups at that institution.

Implications

The findings indicate that age represents a significant determinant of plate waste generation in school catering environments characterised by fixed-portion, no-choice service models. The consistent age effect across measurement periods suggests that developmental and behavioural factors associated with age may fundamentally influence consumption patterns and waste production in standardised catering settings. These results support the implementation of differentiated catering strategies based on student developmental stage to optimise portion appropriateness and reduce waste generation. Age-specific interventions warrant investigation, including portion-size calibration for younger students or structured exposure protocols to less-preferred foods designed to expand taste preferences and foster sustainable consumption behaviours. The variation in age-related waste patterns across individual schools suggests that institutional or operational factors may moderate the relationship between student age and plate waste, meriting further examination.