A behaviourally segmented assessment of the environmental, nutritional, and economic impacts of household food waste in the Republic of Ireland

Household food waste represents a multifaceted sustainability challenge with environmental, nutritional, and economic repercussions. However, no integrated multidimensional assessment has examined how impacts vary across different household food waste behaviours, representing a critical knowledge gap. This study presents the first nationally representative, behaviourally segmented assessment of household food waste in the Republic of Ireland (ROI), integrating life cycle assessment (LCA), nutrient composition, and economic assessment. Data from 966 households were used to quantify food waste volumes across twelve food categories and four behavioural clusters. Environmental impacts were estimated using the ReCiPe 2016 Midpoint (H) method, while nutrient and monetary losses were calculated from compositional databases and retail price data. Irish households were found to discard an average of 21.6 kg of food waste per capita annually, equating to 59.8 kg CO₂ eq, 63.6 m2·year of land use, and 2.75 m3 of freshwater consumption. Calculated economic losses amounted to €82.8 /cap/year, equating to approximately €449 million nationally. Nutrient losses included 16,459 mg calcium, 2092 mg vitamin C, 363 g dietary fibre, and 170 mg iron per person annually. Red meat waste accounted for the largest environmental burden, while fruit, vegetables, and dairy products contributed most to nutrient losses. Behavioural segmentation revealed that High-Spending Disposers generated more than double the waste of Time-Conscious Savers. Scenario analysis indicated that a 50% behavioural shift from high-waste to low-waste clusters by the year 2030 could reduce national food waste by 19%, lower greenhouse-gas and land-use impacts by 31%, and cut annual monetary losses by €87 million. Study findings highlight the multidimensional nature of household food waste and its potential for synergistic mitigation across environmental, nutritional, and economic domains. Policy frameworks integrating behavioural interventions, nutritional framing, and circular-economy metrics are essential for achieving SDG 12.3 and advancing ROI's transition towards sustainable food systems.