Assessment of Household Food Waste and Consumer Behaviours in Portugal Using Smart Scale Technology

Aims: Household food waste represents a major challenge for sustainable food systems, contributing to environmental impacts and unnecessary resource losses. Objective monitoring technologies can complement questionnaire-based approaches, providing more reliable estimates of household food waste generation. This study aimed to characterize household food waste and associated consumer behaviours using a smart scale monitoring system developed by the Jožef Stefan Institute within the framework of the WASTELESS project. This pilot study also represents one of the first applications of the WASTELESS smart scale technology in Portugal.

Methods: Twenty Portuguese households, with 58 residents, were monitored for seven consecutive days using the WASTELESS Scale, an integrated digital system that records the weight, food category, avoidability, and method of disposal of household food waste. Participants also answered a structured questionnaire that covered household composition, socioeconomic characteristics, purchasing habits, dietary patterns, organic waste management practices, and perceived barriers to reducing food waste. Non-parametric descriptive and exploratory statistical analyses were performed.

Results and Discussion: During the monitoring period, households generated 70.33 kg of food waste, which corresponds to 173.2 g/person/day and 502.4 g/household/day. Avoidable food waste represented 57.9% of the total, corresponding to 40.72 kg and 100.3 g/person/day, while unavoidable food waste represented 42.1%, corresponding to 29.61 kg and 72.9 g/person/day. Family size, income, education level, shopping frequency, separation of organic waste, and composting did not show a significant association with total food waste generation. These findings should be interpreted considering the pilot nature of the study, the limited sample size, and the short monitoring period. Most families reported having access to organic waste collection, but only a minority regularly separated food waste. Absence of planning and lack of time were the main barriers reported for reducing food waste.

Conclusions: Smart scale monitoring, combined with behavioural survey data, provided objective evidence on food waste generation in households. The predominance of avoidable waste indicates substantial potential for prevention strategies focused on meal planning, food management, and consumer behaviour. These preliminary findings support the feasibility and usefulness of digital monitoring tools and provide a basis for future larger-scale studies on household food waste.