Designing a healthy and sustainable diet

Many Western countries such as Scotland face the challenge of reducing carbon emissions associated with food systems (Garnett 2011) while also improving dietary nutritional intake (Scottish Government 2016). Both measures together with affordability represent a sustainable diet. The purpose of this paper is to estimate a healthy and sustainable diet for the major demographic groups in Scotland through producing a list of food products which would help create such a diet. The data for the analysis were sourced from the National Diet and Nutrition Survey (NDNS) for the purposes of estimating Scottish food consumption categories and their respective nutrients. The datasets were augmented with prices obtained from 2014 Kantar Worldpanel data in addition to carbon footprint data (cradle to grave). The diet was designed using a linear programming model, which minimised the monetary cost of the diet subject to 22 nutritional constraints based on UK and Scottish dietary recommendations plus a greenhouse gas emission constraint. The results suggest that a sustainable and healthy diet is possible for all the demographic groups. All 22 nutrient constraints were satisfied in the modelling of the healthy and sustainable diet and the cost of the seven-day diet was estimated to be the most expensive for the Female 11-14 group at £18.20. However, the diets are virtually vegetarian based and some quantities of food products are unrealistic, which may pose issues for consumer acceptability.