Abstract: In recent years, food loss and waste (FLW) has become an issue of widespread interest and concern. About 20% of food is lost or wasted throughout the whole food supply chain (FSC), impacting all variables affecting sustainability: environmental, social and economic. In addition, the health crisis caused by COVID-19 produced both changes in FSC due to the lockdown, and alterations in people’s eating habits, creating huge shifts in terms of food security, food access, and FLW. In this framework, the present paper aims to review and analyse the impact of the COVID-19 outbreak on FLW, as well as the main consequences and adaptation measures. The outcomes of the revision evidence that no significant changes were produced in the amount of FLW produced during the outbreak, just a partial reallocation to household. The nutritional content of FLW decreased as consequence of the higher consumption of less nutritional foods and beverages, whereas, on the counterpart, the FLW cost and greenhouse gas (GHG) emissions grew during this period, being this enlargement caused by the household consumption. All the changes and adaptations from food producers and consumers have transformed the primary sector into a more resilient one. Citizens have indirectly accelerated the learning process of food purchase management and responsible consumption, whereas, at the same time, supply chain stakeholders have had adapted their work to online demand. In addition, the COVID-19 pandemic has demonstrated the need for a decentralized FSC, a flexible and forthcoming distribution system, as well as the inclusion of small producers, and the favoring of secondary feeding strategies, such as donations. In short, this pandemic has provided an opportunity to demonstrate that the food system can adapt to changes and only by maintaining them the sector will become more resilient and sustainable.