The global health impacts of future food scenarios

The global food system is highly complex. It is both influenced by and has an influence on health, economic development and the environment. It will face considerable strain over the coming decades as income growth, urbanisation and globalisation lead to shifts towards Western dietary patterns (e.g. high in meat and processed foods) across the developing world. Under these conditions, the challenge is to find a sustainable method to feed the world’s increasing population, whilst considering the trade-offs and synergies between health, environmental sustainability and economic development. One approach is to build global health, environmental and development ‘modules’ that can be coupled to the GTAP database and computable general equilibrium models to estimate the impact of food trade scenarios on these domains. Here we present a multi-state Markov health module that represents the transition of a population cohort in yearly increments. The cohort is divided into four different weight categories: underweight, normal, overweight, obese. The state transition parameters are based on weight-specific risk parameters of all-cause mortality and mortality related to the consumption of specific food categories. The model allows for the calculation of life expectancy and changes in life expectancy resulting from changes in food consumption and a cohort’s weight distribution. The model is calibrated with data from the World Health Organisation (WHO) on age-specific mortality rates and body-weight distributions for 194 countries. Relative risk parameters of food consumption and weight category are inferred from meta-analyses of prospective cohort studies. We outline how the health module can be coupled to economic trade models in order to analyse the global health impacts of future food scenarios. For that purpose, we apply the health module to the global food scenarios for the year 2050 that have been produced by the International Food Policy Research Institute (IFPRI). The health module’s output estimates the changes in life expectancy by region for the different food scenarios. The output complements the results reported by economic trade models which commonly focus on sectoral production and consumption-based welfare. We close by highlighting the possibilities of establishing a dynamic link between the health module and economic trade modules that would allow for feedbacks between the two model frameworks.