Consumption and Greenhouse Gas Emissions Impacts of Population-Wide Adoption of Dietary Guidelines in China.

This paper uses an optimisation model to quantify the necessary food consumption adjustments for Chinese diets to fulfil the requirements in the health-based Chinese Dietary Guidelines (CDG) or WHO dietary guidelines. We further aim to determine whether adopting these guidelines could lead to lower levels of greenhouse gas emissions (GHGE) while maintaining diet affordability. Modelling outcomes under the CDG and WHO scenarios differ significantly from nutritional, GHGE and diet affordability perspectives: relative to observed eating patterns, diets following the WHO guidelines are equally emissions intensive, while diets consistent with the CDG recommendations are less sustainable. Further optimisations imposing significant reductions in GHGE indicate important environmental and nutritional co-benefits can be achieved through the WHO guidelines, while maintaining diet affordability. In the WHO scenario, the maximum diet-related GHGE reduction policymakers could aim for is 30%, since above this threshold, recommended diets would deviate considerably from observed patterns. The CDG model with a 20% emissions reduction does not converge for 64% of the initial data set, casting doubt on the affordability and compatibility of the CDG with China's decarbonisation goal. We recommend that future versions of the CDG be reformulated to closer align with WHO advice and explicitly include environmental considerations.