Food loss and waste (FLW) in developing countries is often high at postharvest stages due to technical and infrastructural constraints, while supermarket expansion has induced organizational, institutional and technological changes in the agrifood supply chains. Here we assess the volume of FLW along a food supply chain (FSC) and analyze the roles that supermarket and non-supermarket channels play in dealing with FLW. The study is based on primary data collected along a tomato chain—from production to retailing—in Cali (Colombia). The results revealed relatively low FLW due to: 1) the diversity of consumer preferences, 2) the reduced harvest-to-sale time, 3) the marketing strategies adopted to sell downgraded and damaged products, and 4) the overlap and complementarity between supermarket and non-supermarket channels. The study highlights the importance of preserving the diversity of these marketing channels to avoid unsold food products, meet the range of consumers' needs, while providing greater marketing opportunities for farmers.