A Multi-Objective Location Model for Kitchen Planning in a Centralized School Lunch Program Considering Cost, Environmental, and Social Impacts

School lunch programs in low- and middle-income countries are increasingly required to meet nutritional, environmental, and social goals. However, existing planning approaches often emphasize cost minimization while neglecting sustainability trade-offs. This study introduces a multi-objective optimization model for determining central kitchen locations and assigning schools under cost, environmental, and social objectives. A lexicographic optimization approach is applied to six policy scenarios using a case study in Balikpapan, Indonesia, due to its rapid urban growth and persistent challenges in establishing equitable and efficient centralized kitchen systems. Results indicate that cost implications remain relatively stable across scenarios, while emissions and employment are highly sensitive to delivery radius and budget constraints. Socially prioritized scenarios increase job opportunities but raise emissions, whereas environmental-focused strategies reduce emissions at the expense of reduced employment impact. Budget reductions exceeding 15% significantly limit service coverage and reduce social impact. The model provides a decision-support tool for policymakers to design cost-effective, inclusive, and environmentally sustainable centralized school lunch systems.