Quantifying the consumption, nutrition, and greenhouse gas emission effects of dietary guidelines in China: a modelling study

Abstract

BackgroundThe rapid nutrition transition China is now ongoing; the so-called westernisation of diets has been negatively affecting both human health and that of the environment. Against this backdrop, the Chinese government released new Dietary Guidelines (CDG) in 2016 and has been actively promoting them since. Our research makes use of quantitative modelling and aims to determine whether adjusting the average Chinese diet, so that it fulfils dietary requirements, could lead to nutritional and environmental co-benefits. Moreover, we want to determine the maximum reduction in greenhouse gas emissions (GHGEs) that could be achieved while simultaneously consuming a healthy diet. MethodsA diet optimisation model is used to simulate, quantify and compare the effects on the consumption of 19 food groups, and associated levels of GHGEs, resulting from two different scenarios: consumers complying with either the CDG or the WHO dietary norms. Subsequent simulations set maximum emission limits for the optimised diets and progressively reduce emissions by 5%. Four waves of consumption and price survey data from the China Health and Nutrition Survey are used in the analysis, while LCA estimates of GHGEs are compiled from the appropriate literature. FindingsPreliminary results show that outcomes under the two scenarios differ significantly, both nutritionally and in terms of GHGEs. Adopting the CDG would lead to a considerable intensification of emissions for both men and women, while adhering to the WHO norms would marginally increase emissions for women and slightly decrease emissions for men. However, we find a 10% reduction in GHGEs relative to current levels could be achieved, under both scenarios, through healthy and realistic dietary change. The maximum decrease in emissions achievable in the CDG model is 15%. The WHO models with a more drastic decrease in emissions (30% and 40%) involve major dietary change and lead to less balanced and varied diets compared with existing ones. InterpretationOur quantitative estimates show the potential for dietary guidelines to lead to environmental and health co-benefits, but only if they are specifically formulated to include environmental considerations. Achieving a major reduction in GHGEs through diets involves clear trade-offs between nutritional and environmental considerations. FundingNone.