Optimization Of Residents’ Food Consumption Structure With Consideration Of Greenhouse Gas Mitigation

With the rapid socio-economic development,the dietary structure of Chinese residents was undergoing tremendous changes,with increasing intake of animal-sourced food.Particularly,the intake of meat and edible oil led to a significant increase in greenhouse gas（GHG）emissions from food system.In 2020,China committed to reach peak levels of total GHG emissions in 2030.Thus,it is significant for optimizing the resident dietary structure to peak GHG emissions and acquire nutritional balance.In this study,an integrated approach was developed by incorporating autoregressive integrated moving average（ARIMA）,multiple linear regression,and an interval linear programming model into a general life cycle analysis（LCA）framework.In detail,（i）the GHG emissions from food system were assessed in the LCA framework;（ii）the variations in food demand influenced by socio-economic development were identified;and（iii）a specific model for dietary structure optimization that focused on GHG emission reduction and dietary nutritional balance was established.The variations of food supply in different seasons and food demands in different age and gender groups were considered in the model.A case study was proposed to illustrate the application of the approach in Guangdong Province,China.The results were described as follows:（a）In terms of food GHG emission inventory of Guangdong Province,the GHG emission factors of animal-sourced food were much higher than those of plant-sourced food.Compared with those of other animal-sourced food,GHG emissions of mutton was biggest（i.e.,9.35 g CO₂ eq/g）,and 6.6 times more than those of chicken.Compared with those of other plant-sourced food,GHG emissions of vegetables（i.e.,0.035-0.091 g CO₂ eq/g）were much lower than those of grain and fruit due to the variations of agricultural inputs such as pesticides and fertilizers.（b）The variations in dietary preference of residents in Guangdong indicated that 1)the predicted cereal demand based on multiple linear regression models would decrease significantly.For example,per capita intake of cereal in 2025 would be 45.7%lower than that in 2000;2)the per capita intake of meat（i.e.,149 g/day）would increase significantly in2025,compared with that n 2000（i.e.,65 g/day）;3)there would be little change in vegetable intake and a slow increase in the intake of other food;and 4)GHG emissions in food system increased lowly from 2000 to 2012,and iwould increase rapidly from 2022 to 2025.（c）According to the optimized dietary strategies,the intake of plant-based food would increase significantly,supporting most of the nutrients（e.g.,vitamins）required by the human body.The optimized diet in Guangdong Province would reduce 6%-11%GHG emissions,compared with the projected dietary preferences in 2025.Food intake of adult men and adolescent men would be generally higher than that of other groups,which would also lead to the highest GHG emissions.Food intake and related GHG emissions of older women would be the lowest.Specifically,the GHG emissions from food consumption of adults would be 11.2%higher than those of the elderly women,and the GHG emissions from food consumption of adolescents would be 4.7%higher than those of adults.The GHG emissions from food consumption of men would be 12.9%higher than those of women.From the perspective of dietary structures,the intake of meat and edible oil would decrease by 18.9%and 16.1%,respectively;the intake of vegetables and fruits would increase by10.4%and 12.3%,respectively;eggs,milk and aquatic product intake would increase by18.6%,19.3%and 19.6%,respectively.Also,compared with GHG emissions of food intake in other seasons,GHG emissions of food intake in autumn would be the least[i.e.,871-944 g CO₂eq/（person·day）];and GHG emissions from food intake in spring would be the biggest[i.e.,901-1033 g CO₂ eq/（person·day）].