Nutrient quality, environmental impact, and cost of Chinese diets: a benchmarking optimization approach

Purpose: Design Chinese diets that are more nutritious, and have lower environmental footprints and cost, while accounting for diet preference. Methods: Food consumption data of 4889 men and 5435 women adults were collected via 3-d 24-h dietary recalls in five regional subgroups (Metropolitan cities, Northeast, East, Southwest, and Central region) covered by the China Health and Nutrition Survey 2011. Data envelopment analysis (DEA) model was applied to benchmark diets that had higher adherence to food-based dietary guidelines. Optimized diets were obtained by combining benchmarked diets in the studied population that complied with different sustainability goals: maximized nutrient quality (Nutrient Rich Diet score, NRD15.3), minimized greenhouse gas emissions (GHGE), minimized diet cost, maximized diet preference, and an integrated scenario. Furthermore, trade-offs between sustainability indicators were assessed. Results: When nutrient quality, environmental impacts, and diet cost were optimized within each regional subgroup, the NRD15.3 increased 22–35%, GHGE decreased 17–38%, total water use (TWU) decreased 14–35%, land use (LU) decreased 21–33%, and diet costs decreased 23–32% compared to observed diets. When optimizing diet preference, more than 90% of food consumption remained similar as observed diets. When the four objectives were considered simultaneously, all indicators improved ~ 20%. In trade-off analyses, higher nutrient quality was accompanied by increased environmental impacts and diet cost. Conclusion: Diet improvement towards more nutritious, environmentally sustainable, affordable, and culturally acceptable is feasible in China. During the transition of the food system, iterative applications of the DEA model to changed dietary habits can inform policymakers to finetune diet recommendations towards sustainability.