Reducing Greenhouse Gas Emissions (GHGE) through Affordable and Nutritionally Adequate Diets for UK Families Optimized for Cultural Acceptability
Background and Aim: Modification of dietary patterns can contribute to reduce global warming as the production of food is associated with app. one fourth of global GHGE. However, holistic solutions are needed that take nutritional adequacy, cost and cultural acceptability into consideration.
Methods: Total GHGE from the foods consumed by a 4-member UK family per day (Food Basket, FB) were calculated based on previous life cycle assessment data1. Prices of 15,133 food items from different online food retailers were obtained and median prices for comparable products were used to calculate cost of FBs. All FBs met the recommendations on nutrient intake (RNI) and macronutrient ratios (AMDRs). To achieve cultural acceptability, FBs with a 40% reduction in GHGE were optimized by linear programming for best possible similarity to the distribution of 67 foods/food groups as reported by the National Diet and Nutrition Survey (NDNS). The effect of implementing the Eatwell
Guide was also investigated.
Results: The daily FB of the reference family was associated with 30.2 kg CO2eq and dropped to 28.4 kg after implementation of the Eatwell Guide recommendations (-6.0%). Implementation of the Eatwell Guide and enforcing nutritional adequacy resulted in a 10.2% average relative deviation (ARD) from the
observed diet. Compared to the observed diet, the envisioned 40% reduction in GHGE to 18.2 kg CO2eq was achieved at comparable cost (26.87 vs. 26.27£) and was associated with a marginal increase of the ARD to 11.3%. Food groups to be reduced the most to achieve GHGE reduction while following the Eatwell Guide and meeting nutritional recommendations were sugars, beef, biscuits, milk and pork while fish, "other vegetables" and cereals had to be increased.
Conclusion: When following recommendations of the Eatwell Guide, only relatively minor additional deviations from the reported consumption of food groups by UK families have to be applied to achieve a 40% reduction in GHGE on top of that.
1Audsley E et al. (2009). How low can we go? An assessment of greenhouse gas emissions from the UK food system and the scope to reduce them by 2050. FCRN-WWF-UK.