Dietary changes to mitigate climate change and benefit public health in China.

Dietary change presents an opportunity to meet the dual challenges of non-communicable diseases and the effects of climate change in China. Based on a food survey and reviewed data sets, we linked nutrient composition and carbon footprint data by aggregating 1950 types of foods into 28 groups. Nine dietary scenarios for both men and women were modeled based on the current diet and latest National Program for Food and Nutrition. Linear uncertainty optimization was used to produce diets meeting the Chinese Dietary Reference Intakes for adults aged 18-50years while minimizing carbon footprints. The theoretical optimal diet reduced daily footprints by 46%, but this diet was unrealistic due to limited food diversity. Constrained by acceptability, the optimal diet reduced the daily carbon footprints by 7-28%, from 3495 to 2517-3252g CO2e, for men and by 5-26%, from 3075 to 2280-2917g CO2e, for women. Dietary changes for adults are capable of benefiting China in terms of the considerable footprint reduction of 53-222Mt.CO2eyear(-1), when magnified based on the Chinese population, which is the largest worldwide. Seven of eight scenarios showed that reductions in meat consumption resulted in greater reductions in greenhouse gas emissions. However, dramatic reductions in meat consumption may produce smaller reductions in emissions, as the consumption of other ingredients increases to compensate for the nutrients in meat. A trade-off between poultry and other meats (beef, pork, and lamb) is usually observed, and rice, which is a popular food in China, was the largest contributor to carbon footprint reductions. Our findings suggest that changing diets for climate change mitigation and human health is possible in China, though the per capital mitigation potential is slight lower than that in developed economies of France, Spain, Sweden, and New Zealand.