Transition towards sustainable diets: Multi-objective optimization of dietary pattern in China

Global diversity in food cultures has led to a variety of dietary patterns, the evolution of which can significantly impact greenhouse gas (GHG) emissions. To address the dual challenge of climate change and malnutrition, we need to examine feasible pathways towards sustainable diets that balance nutritional adequacy, environmental impact, and cultural acceptability. We propose an optimized dietary transition pathway in China, which aligns with the nation's dietary guidelines (DGs) while aiming to reduce diet-associated GHG emissions and maintain the cultural food preferences. We also examine how the current dietary patterns will change under three different scenarios: 1) meeting nutritional needs (N), minimizing GHG emissions while maintaining nutritional standards (NE), and sustaining cultural acceptance and maintain GHG emissions at a low level while ensuring standard nutrient intake (NEC). We analyze data from 31 provinces in China between 2000 and 2020 to explore sustainable dietary patterns. In this period, plant-based food consumption has experienced a substantial 12 % decrease, in contrast to the 68 % increase in animal-sourced food intake. Meanwhile, diet-associated GHG emissions in China have increased by 17 %. However, dietary nutrition remains below national standards. The diet-associated GHG emission under NEC is 63.43% lower than N and is 7.04% higher than NE, while NEC in cultural unacceptability is 28.39% lower than NE. Our optimized dietary patterns demonstrate the potential to achieve the national nutrition standard, significantly cut GHG emissions, and retain higher cultural acceptability. Acknowledging the regional disparities in sustainable dietary pathways, we propose the implementation of customized provincial directives aimed at fostering compliance with these favorable trends. Our study offers critical policy implications towards achieving a sustainable diet in China, which contributes to managing the complex trade-offs among nutrition, cultural preferences, and environmental impact.