Nutritional Quality and Environmental Impact of Public School Meals: Evaluation of Current Meals and Potential Benefits of Vegetarian Diets for Sustainable Improvement

School feeding is a fundamental component of public policies aimed at promoting health, improving educational outcomes, reducing inequalities, and guaranteeing the human right to adequate food. This study aimed to evaluate the nutritional quality of school meals offered to public school students in a federal unit of Brazil, quantify the environmental impacts using carbon and water footprints, and simulate potential reductions through a strict vegetarian menu. This cross-sectional, descriptive study analyzed 130 daily menus (390 meals) from full-time public schools in the Federal District of Brazil in 2024. Nutritional quality was assessed based on energy, nutrients, food groups, degree of processing, and food origin. Carbon and water footprints were estimated using literature-based indicators. A nutritionally adequate strict vegetarian menu was then developed and compared with the observed menus. The current menus presented good overall nutritional quality, with high food diversity and predominance of fresh or minimally processed foods. Most nutritional parameters met the recommended levels; however, protein and saturated fat exceeded the recommended limits. Animal-based foods accounted for most of the carbon and water footprints. The simulated strict vegetarian menu demonstrated significantly lower environmental impacts while maintaining nutritional adequacy. These findings highlight the importance of integrating nutritional and environmental strategies, such as a weekly "Meatless Monday" initiative alongside food and nutrition education, to improve student health outcomes and reduce the environmental burden of public school meals. Incorporating environmental sustainability criteria into school meal planning and public food procurement may advance nutritional quality, resource efficiency, and climate goals, positioning school feeding programs as strategic instruments for sustainable development.