Diner leftover food waste: Measurement, drivers, and potential effects — a case study of an Asian noodle restaurant

Food Loss and Waste (FLW) has emerged as a significant global concern, undermining sustainability initiatives and exacerbating climate change. A comprehensive understanding of FLW is essential for developing reduction strategies and assessing its environmental impacts. However, with limited research on FLW in the food service sector, challenges persist, particularly in the consistency of FLW data across the food supply chain. The inclusion of liquid and solid Food Waste (FW) is crucial for effective FLW management, yet a great deal of research on liquid FW remains scarce. Additionally, an examination of FW and packaging use reveals conflicts between environmental objectives and hospitality industry practices. This case study investigates FW production at a noodle restaurant in northern British Columbia, with a particular focus on how consumer behaviour, especially the use of doggy bags, affects FW. The primary objective is to classify and quantify solid and liquid types of FW. The second objective involves developing a statistical model to analyze factors contributing to FW, with a focus on the impact of a doggy bag fee. Finally, the study evaluates the environmental consequences of FW, providing insights to balance FW management with environmental impact mitigation in food service settings. The study examined solid and liquid FW in an Asian noodle restaurant, focusing on post-consumer FW and drivers, including the influence of additional costs for taking leftovers home. FW data were collected over six months (September 2022 - March 2023), and direct weight and composition analysis were used to classify FW into solid and liquid forms. A Regression Discontinuity in Time (RDiT) model assessed the effect of additional charges on FW, considering explanatory variables such as daily sales, meal size, and weather. Carbon dioxide equivalent CO2 emissions were estimated based on FW data and the model’s findings. The daily average FW was 2.21 kg, with solid FW averaging 0.65 kg and liquid FW 1.56 kg, revealing a significant correlation between them. RDiT analysis showed that the 10-cent surcharge of doggy bags significantly impacted liquid FW immediately, with limited and short-term effects on solid FW. A slight sustained effect on solid FW was observed, but it remained minimal overall. Daily sales were significantly associated with both types of FW, while smaller meal portions did not exhibit the expected inverse relationship. The doggy-bag surcharge was insuffcient to offset environmental costs in CO2e scenarios, suggesting that elevated fees for take-out containers are necessary. Despite its limitations, this study provides novel insights into FW categorization and suggests that single-use plastic regulations and sales influence FW, although not for smaller meals. The findings emphasize the need for increased fees to address environmental costs of restaurant FW effectively. Future research should explore more comprehensive strategies to reduce FW and its environmental impacts.