Net Yield Efficiency: Comparing Salad and Vegetable Waste between Community Supported Agriculture and Supermarkets in the UK

Food security is high on the global agenda. Two factors make it particularly pressing: the continuing rise in the global population and the failure to adequately feed the current one. An area that has been the focus of much recent attention has been food waste; the FAO estimates that as much as a third of all food is lost or wasted. This paper argues that by taking a food system approach that accounts for yields as well as loss and waste in distribution and consumption, we can compare the contribution of different food systems to food security. A novel concept of ‘Net Yield Efficiency’ (NYE) is introduced that accounts for this. We present an illustrative case study of levels of fresh vegetable and salad waste in the supermarket-controlled food system compared with a Community Supported Agriculture (CSA) scheme. This case study explores whether the CSA and its members are less wasteful than the supermarket system. The study found that when all stages of the food system were measured for waste, the CSA dramatically out-performed the supermarket system, wasting only 6.71% by weight compared to 40.7 - 47.7%. Even accounting for difficulties in waste estimation, the findings underline the disparity between these systems. On this basis, the paper argues that the NYE measure provides a more accurate picture of food system performance than current measures which tend to focus on yield alone.