From plate to prep: Designing behavioral intervention tools to reduce food waste in restaurant staff and customers

Food waste in the catering industry poses significant economic, social, and environmental challenges globally. While existing research predominantly focuses on consumer behavior, this study addresses critical gaps through two low-cost intervention tools: consumer-facing table cards (leveraging social norms and emotional affect) and staff-targeted commitment posters (leveraging commitment). Field experiments across three à la carte restaurants assessed efficacy via waste monitoring and Theory of Planned Behavior (TPB) questionnaires. Table cards reduced per capita customer food waste by 29–54 % (p < .001) compared to controls, with comparable efficacy between social norm and emotional affect strategies. However, efficacy was confined to individual/pair diners, eliminating baseline waste disparities between dining group sizes. Commitment posters decreased per capita food waste by 21.4 % (p < .05) across sites, though effects varied by restaurant context. Critically, posters induced significant shifts in staff psychological constructs: agreement with counterproductive behavioral beliefs plummeted nearly 50 % (p < .001) and perceived barriers to behavioral control declined 42 % (p < .001), alongside significant improvements in attitudes, subjective norms, and intentions across all core TPB constructs. This research delivers empirically validated, scalable tools that bridge consumer and employee interventions, contributing directly to food waste reduction in Chinese à la carte restaurants.