Greenhouse gas (GHG) emissions significantly affect the environment, public health, and socioeconomic systems. Many countries and organizations have launched sustainable strategies to ease damaging consequences caused by the global climate change. Food services contribute greatly to greenhouse gas emissions. Service factors involved are food waste, the type of food service provided, and the use of single-use plastic products. For example, a single-use plastic food container related greenhouse gas emissions ranges from 0.16 to 0.48 kg CO2e. We have encouraged staffs to use reusable food containers since July 2024, and we shared the related information with all of staffs via emails and official website. This study aimed to evaluate the impact of sustainability initiatives—particularly the promotion of reusable food containers and a variable price buffet system. In our staff restaurant, 3 types of food services were in place: (a) variable price buffet service, (b) fixed price canteen service, and (c) fixed price box lunch. Data were first collected from July 2023 to December 2024, and then analyzed according to the following 4 aspects: (a) the average number of lunches consumed each day, (b) the amount of reusable food containers used, (c) the reduction of greenhouse gas emissions, and (d) an observation of food waste in food services. Statistical analysis was carried out using the SPSS software, version 22. We found that in 2024, the restaurant provided 1,200 to 1,800 meals/day during lunch time. Within these meals, 37.1% were from variable price buffets, 18.8% were from fixed price canteen, and 44.1% were from fixed price box lunches. First, in 2024, the use of reusable food containers in the variable price buffet averaged at 50% (47.9% to 56.3% on a monthly basis). In comparison to the period July to December 2023, our results show a significant increase in use of reusable food containers from July to December in 2024 (p < 0.05). Second, from July to December 2024, an estimated GHG emission reduction of 15,387–46,163 kg CO2e. Finally, based on the observation of food waste in different types of food services, there was almost no food waste in variable-price buffet service. In the literature, Matzembacher et al have reported that the variable-price buffet service generates 116% less avoidable food wastes when compared with the fixed price canteen service(1). With the increasing public awareness of sustainable practices aimed at environmental protection, the adoption of reusable food containers and a variable-price buffet model effectively reduced plastic waste and GHG emissions. These initiatives included the implementation of a variable price buffet service to reduce food wastes and minimizing single-use plastic items and carbon footprints.