Encouraging the planetary health diet via food taxes and subsidies: a model concept

BACKGROUND: Several studies simulated the effect of food taxes and subsidies on health and environmental outcomes, but they are diverse and rarely model both health and the environment. Incomplete models’ estimates can be misleading: outcomes can be detrimental in a topic that was not included in the model. The aim of this study is to map the important areas affected by planetary food taxes and subsidies and to build a comprehensive model concept. METHODS: A systematic literature search database was used to map the areas. An initial model concept was then iteratively redesigned and finalized. RESULTS: The main included outcome areas are health, dietary, financial, and environmental outcomes, the latter assessed in diverse areas, like freshwater use, land use, and biodiversity loss. The elements which can greatly influence the model estimates should be carefully assessed, like consumption change, which lies in a central part of the model: included complementary and substitution foods, and consumed diet mass stability is assumed to be more accurate. Health outcomes include the health effects of climate outcomes, affecting not just the modeled region but the whole world population. The input data is scarce, especially reliable price elasticity estimates, and the health effects of climate change. CONCLUSIONS: The stability of consumed diet mass is still not agreed upon but leads to a biologically more accurate outcome. The inclusion of the health effects of climate outcomes can broaden the picture and emphasize the global nature of our food choices. Input data for building a comprehensive model is currently not optimal, more data are needed on consumption change and the health effects of climate change. The next step for public health could be to model food taxes and subsidies for Europe and to compare the estimates with previous models, also to map the stakeholders’ impressions regarding such a tax and subsidy. KEY MESSAGES: • We need comprehensive models of food taxes and planetary health to make responsible decisions. • A model concept was made which includes important areas and relations between them.