Given the multidimensional impact of food waste on the environment, economy, and public health, this research investigates perceptions, behaviours, and practices of food resource management in rural guesthouses, taking the Rucăr–Bran agro-tourism area as a case study. The region was selected due to its relevance to rural tourism in Romania, given the density of guesthouses, the traditional gastronomic offer, and the direct relationship between producer and consumer. The main objective is to identify the determinants of food waste from the perspective of both managers and tourists, with the aim of formulating sustainable recommendations applicable to the entire rural guesthouse sector, in line with the principles of the circular economy and the One Health concept. The methodology included mixed-method design with guesthouse managers and questionnaires to tourists on holiday eating behaviour. The data was collected between August and December 2024, using a conventional sample consisting of 30 rural guesthouse managers and 100 tourists. The questionnaires were designed using the funnel design, including dichotomous, multiple choice and Likert scale questions. The results show significant wastage generated by oversized portions, lack of planning in provisioning and tourist habits linked to excessive consumption. The study proposes a set of recommendations for circular food resource management, including adapting menus to real demand, reusing surplus food, composting waste, and raising tourist awareness, thereby supporting the economic sustainability of rural guesthouses and protecting the local ecosystem in accordance with One Health principle.