【摘要】 饮食调整被视为缓解气候变化的可行途径。本研究以中国特大城市北京和上海为例，探究居民膳食结构演变特征，采用食物碳足迹法测算食物碳排放量，并构建多目标优化模型以确定与文化偏好、经济负担和营养需求相适应的低碳膳食转型方案。研究发现：1992—2021年，北京和上海居民总食物消费量分别经历了波动下降和缓慢上升的时期，其膳食结构均向动物性饮食演变。肉类消费的显著增加导致北京和上海居民食物碳排放量上升，居民人均食物碳排放量分别增长了37.2%和25.2%。基于多目标优化模型，与2021年实际居民膳食结构相比，减少动物源食品特别是肉类的消费可以满足文化可接受、经济可负担的多元目标，并分别减少北京和上海居民食物碳排放总量92.14 t和212.65 t。本研究提供了特大城市居民膳食结构演变及其碳排放效应的新见解，强调了优化饮食作为促进全球可持续发展的优先事项的重要性。更多还原

【Abstract】 Dietary modification has been suggested as a viable path to mitigate climate change. This study explored the evolution of dietary structures in China’s megacities and quantified food-related carbon emissions using the carbon footprint method. Then, we developed a multi-objective optimization model to identify low-carbon dietary options that align with cultural preferences, economic feasibility, and nutritional requirements. We found that from 1992 to 2021, the total food consumption of residents in Beijing and Shanghai experienced a period of fluctuating decline and slow rise, respectively, with their dietary structures both shifting toward animal-based diets. Additionally,the significant increase in meat consumption led to increasing food carbon emissions in Beijing and Shanghai, with per capita emissions rising by 37.2% and 25.2%, respectively. According to the multi-objective optimization model,shifting towards reduced consumption of animal products, particularly meat, would align with culturally acceptable,economically feasible, and low carbon emission goals in Beijing and Shanghai, potentially leading to reductions of 92.14 t and 212.65 t in total food carbon emissions compared with the actual in 2021, respectively. This study enhances understanding of the changing dietary patterns in urban areas and their associated carbon emissions, and emphasizes the significance of optimizing diets as a key priority for advancing global sustainable development.更多还原