Macdiarmid, J., Kyle, J., Horgan, G.W., Loe, J., Fyfe, C., Johnstone, A.M. and McNeill, G.
||Background: Dietary recommendations have focused on requirements for health and tend not to consider the environmental impact of food production and consumption. Compatibility of the dietary recommendations for health with environmental sustainability needs to be determined.
Objective: To construct a 7-day diet with significantly lower greenhouse gas emissions (GHGE) than the average current UK diet, while also meeting dietary requirements for health.
Design: Linear programming was used to construct a sample diet that minimised GHGE while still meeting food, energy and nutrient requirements for an adult woman in the UK. Nutrient composition and GHGE data for 82 different food groups were used, and to ensure a realistic variety and balance of food items consumer acceptability constraints were placed on the model to limit the amount of each food group included in the diet.
Results: A 7-day sample diet was created that met dietary requirements and achieved a significant reduction in GHGE. It was possible to incorporate a wide variety of food without eliminating any food groups (e.g. meat, dairy products) but the amounts of these foods were reduced compared to the current diet. The retail cost of the diet was comparable to the average UK expenditure on food.
Conclusions: This study illustrated that many of the principles of a healthy diet are consistent with the dietary changes needed to reduce GHGE to tackle climate change. Individual food groups do not need to be eliminated, but the range and quantities of food need to be rebalanced to benefit health and the environment.