Whydoes food loss and wastematter for food security-from the perspective of causeand magnitude

Food security has raised crisis alarms all over the world. Especially nowadays, conventional agriculture is threatened by climate change and extreme weather, and the agri-food system is loading the increasing population burden. Food loss and waste (FLW) have gotten more and more attention. Still, the main research focus is on a narrowed and specific stage of the food value chain of specific food types in a particular area, which lacks an overall comprehensive understanding of this topic from a broad view. This review aims to provide a comprehensive description of food loss and waste and provide a useful theoretical background to public decision-makers and individuals to reduce food loss and waste for a better and more sustainable society, economy, and environment. Secondary research and content analysis are used in this review as methodology, following Michael E. Porter’s value chain theory, to analyze and simplify the sustainable path (in light of the cause and magnitude of food security based on the nexus between food security and food loss and waste across the entire food value chain (from the main manifestation of FLW: agricultural production stages, such as cultivation or breeding and storage, post-harvest processing and distribution, and retail and consumption. We also provided the Ishikawa model diagram to better explain the causes of food loss and waste. And other manifestations, such as the COVID-19 and Russia and Ukraine war). To conclude, reducing food loss and waste is crucial for sustainable food security, but the manifestation of FLW differ in different stage of the value chain and different food types. Generally speaking, production sees the most loss, while consumption sees the most waste. Therefore, we suggest both public and private should be aware that producing more food and utilizing food resources properly along different stages of the value chain is equally important.