| Sumario: | Background
The EAT–Lancet (EL) report made a convincing case that a transformative diet shift could yield substantial health benefits while helping to respect key planetary boundaries. Shifting to a more plant-based EL diet requires an unprecedented break from historic trends of rising meat consumption. By exogenously shifting diets, existing studies do not provide guidance on how to shift diets. In this study, we model specific policies that might achieve such a dietary shift and their potential economic, environmental, and distributional impacts.
Methods
In this economic modelling study, we used MAGNET, a global computable general equilibrium model, to explore how diets might be shifted from the business-as-usual trend of increased meat consumption between 2025 and 2050. We defined a policy bundle of three types of context-specific interventions: (1) nudging and information to shift consumer decisions, (2) adjusting fiscal policies by removing taxes on encouraged foods and subsidies on discouraged ones, and (3) introducing new price signals, such as taxes on high-emission foods and subsidies for encouraged foods. To evaluate how choice of interventions affects economic, environmental, and distributional outcomes, we analysed interactions of combined interventions and compared the policy bundle to an exogenous shift to the EL diet.
Findings
The EL diet recommendations cannot be reached by the policy bundle. While reducing overconsumption and underconsumption, the policy bundle left a big gap with EL diet recommendations (3 times the recommended intake for red meat, and only 80% of recommended fruit and vegetable intake, 50% for pulses and nuts). No single intervention from the policy bundle shifted all diet components in the desired direction. Decomposition of the policy bundle showed the importance of regional context. In low-income regions, taxes and subsidies accounted for the largest share in the diet shift. In other regions, nudging and information had a stronger effect than did subsidies. The exogenous EL diet scenario assumed a shift in diets beyond the range observed in empirical studies and produced a counterproductive feedback by reducing the affordability of the EL diet. GHG emissions from the primary sector (agriculture and fisheries) decreased more with the policy bundle (–4 GTon CO2 equivalent), as GHG taxes provided incentives to reduce fossil-based inputs lacking in the consumer-focused exogenous EL diet scenario (–3 GTon CO2 equivalent). The shift away from fossil-based inputs also led to an increase in agricultural land area (27 million ha) with the policy bundle, while the exogenous EL diet scenario resulted in a decrease in agricultural land (–35 million ha). Affordability for the average household decreased when exogenously shifting the EL diet (EL diet costs increased 26·1%, household income 0·2%), but it increased with the policy bundle as subsidies lowered EL diet costs (–4·4%) more than it lowered income (–2·0%). Affordability judged against daily wages worsened most when exogenously shifting the EL diet (27·7% of the workforce) and increased slightly with the policy bundle (24·8% of the workforce). Most of the affected workers were in encouraged primary sectors (fruit and vegetables, pulses and nuts, fish), but the negative effects extended to the non-food sectors with the exogenous EL diet.
Interpretation
The interventions chosen to change diets matter for the shift that can be attained and for the direction and size of the environmental, affordability, and distributional impacts. Price incentives can be a more effective, scalable, and just way to shift diets than the often preferred shift in consumer decisions, which make the EL diet more costly. Part of the trade-offs could be addressed by expanding the policy bundle with interventions to lower prices of encouraged foods (productivity increase, food loss and waste reduction) or reduce GHG emissions of food and non-food production, and with regulation of agricultural land expansion to reduce pressure on biodiversity. Increased productivity in lower-income regions could address the effect of past limited access to food and non-food technologies driving an increased reliance on imports in all scenarios. If designed well, it could improve affordability by lowering prices while increasing wages. Stimulating imports might help moderate prices of encouraged foods in case of unsurmountable local production limitations or preference for investing in manufacturing and services. These additional interventions address price and income concerns but are likely insufficient to attain a global shift to the EL diet, as food consumption is determined by more than affordability and nutritional needs.
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