The issue of food losses and waste has recently been given high visibility. According to FAO (2011), almost one-third of food produced for human consumption—approximately 1.3 billion tonnes per year is either lost or wasted. Food losses happen at the earlier stage of food chains; major issues are the post-harvest losses mainly in developing countries, the development of infrastructure and the most suitable technologies to address them while food waste happens at retailing and consumption stages mainly in developed countries but also as an increasing concern in developing countries. Food losses and waste can be first seen as a reduction of food availability for the poor and hungry. By reducing the amount of food available, they also have an impact on prices and thus on access to food. reducing food losses and waste would also reduce the pressure on natural resources. Reducing food losses and waste appears thus as emblematic of better resource efficiency, a key dimension of more sustainable food systems. The Committee on World Food Security (CFS) in its thirty-ninth Session (October 2012) requested the High Level Panel of Experts (HLPE), to undertake a study on ‘Food losses and waste in the context of sustainable food systems’ to be presented to the Plenary in 2014. Causes of food losses and of food waste are very different and call for very different solutions. Most of food losses can be traced back to biophysical, including biosafety aspects, or technical causes. Food waste is often linked to behavioural causes. Reducing food losses and waste appears thus as emblematic of better resource efficiency, a key dimension of more sustainable food systems.Food loss refers to a decrease in mass (dry matter) or nutritional value (quality) of food that was originally intended for human consumption. Food waste refers to food appropriate for human consumption being discarded, whether or not after it has beenkept beyond its expiry date or left to spoil and both occur between the moment when a product is ready to be harvested to the moment when it is consumed. Sustainable food systems can be contemplated at different scales, including regional scales. How food losses and waste ultimately impact the sustainability of food systems (and how solutions can be found) is to be looked within scales, but also across scales, including regional ones. For cultural or for economic reasons, some systems generate waste which for another system is useful resources or food. Enabling the transfers of those foods from regions where they are considered not edible to regions where they are considered edible might be seen as a contribution to the reduction of food losses and waste across geographic scales, as well as a contribution to food and nutrition security of poorer people. FAO estimates that roughly one-third of all edible food produced for human consumption is wasted or otherwise lost from the food supply per year, or about 1.3 billion metric tonnes. The FAO estimates that the per capita food lost by consumers in Europe and North America is 95-115 kg/year, while this figure in Sub-Sahara Africa and South/Southeast Asia is only 6-11 kg/year. Without accounting for undesirable gas (methane) emissions from land use change, the carbon footprint of food produced and not eaten is estimated at 3.3 Gt of CO2 equivalent. The direct economic cost, based on producer prices only, is about USD 750 billion. Processing techniques also fractionate food into different components, for example, extraction of juice from fruits resulting in loss of nutrient and bioactive components in non-utilized leftover residue including losses due to spillage and degradation during industrial or domestic processing, e.g. juice production, canning and bread baking. Losses may occur when crops are sorted out if not suitable to process or during washing, peeling, slicing and boiling or during process interruptions and accidental spillage. These are either discarded as waste or are channeled into non-food use. In dried fruit and vegetables, significant amount of nutrients especially vitamins are lost during drying and other pre-drying processes such as blanching. In dried fruit and vegetables, significant amount of nutrients especially vitamins are lost during drying and other pre-drying processes such as blanching. As a result, even though the food is preserved for later use, its nutritive value is lower. Food loss along the food chain be avoid by: • Developing a harmonised definition and methodology for gathering data and estimating food loss. • Paying particular attention to food wastage when developing policy and evaluating applications for new innovations that have the potential to prevent spoilage and food loss. The impact on food loss should be taken into account in the impact assessment for relevant policies.