Food loss and waste occurring early in the food supply chain leads to increased resource wastage, including land, water, fertilisers, pesticides, energy, and labour. Targeting food loss and waste prevention benefits various aspects such as food security, productivity, economic growth, climate change mitigation, resource conservation, and waste management. Understanding the causes of food loss and waste is crucial for the design of effective solutions and their prioritisation. The purpose of this study was to investigate the risk factors and underlying causes of FLW in leafy vegetables, spanning from agricultural production to retail. To achieve this, the research methodology encompassed a case study conducted among small-scale producers and retailers. A comprehensive approach was adopted by integrating a systematic literature review of global food loss and waste causes and those specific to the Latin American context. This approach was complemented by exploratory research, involving interviews with various stakeholders, coupled with root-cause analysis. A methodology was developed for the creation of a causal map, incorporating the 'Five Whys' technique, the current reality tree, and an interrelationship diagram. The study's findings underscore the critical role of retailer-supplier dynamics in the management and flow of products, identifying a significant research gap in the development of comprehensive strategies for waste reduction. By exploring these dynamics, particularly in the context of take-back agreements and the lack of public policies incentivizing food loss and waste reduction, the research reveals the multifaceted nature of food loss and waste and the necessity for collaborative efforts across the supply chain to mitigate its impacts. The application of the structured methodology provides valuable insights into the root causes and critical risk factors of FLW, offering a foundation for the development of integrated strategies aimed at reducing food loss and waste and advancing towards global sustainability goals.