Animal source foods (ASFs) contribute significantly to negative environmental impacts, including land-use change, water depletion, biodiversity loss, and greenhouse gas (GHG) emissions. While ASF consumption supports nutrition, especially in low-income settings, overconsumption poses public health risks in many countries. Encouraging reduced ASF consumption is crucial for climate change mitigation, health objectives, and sustainable resource use. However, global ASF consumption is projected to continue rising. Plant-based diets are gaining traction in high-income countries, but a global shift remains challenging. Novel plant-based alternatives for meat and milk offer a potential solution by providing behaviorally viable substitutes. While local environmental benefits of these alternatives are known, their large-scale global impacts are less understood. This study addresses this gap by providing a comprehensive, system-wide assessment of a large-scale global substitution of ASFs with novel alternatives.

Existing research on the impacts of novel plant-based alternatives has limitations in scale, scope, and the consideration of impacts. Many studies focus on local or regional contexts, neglecting the complex interplay of global food systems. Moreover, these studies often examine only a limited set of impacts or do not fully capture future market developments. The current study aims to overcome these limitations by employing a dynamic, global, system-wide analysis that comprehensively explores the various environmental and social implications of the transition to novel plant-based alternatives.

The researchers used the Global Biosphere Management Model (GLOBIOM), an economic partial equilibrium model integrating global agriculture, bioenergy, and forestry sectors. The model incorporates hypothetical plant-based recipes designed to be nutritionally equivalent to animal products, considering realistic ingredient sourcing and existing food manufacturing capabilities. Several scenarios were developed, varying the substitution rate of ASFs (10%, 25%, 50%, and 90%) by 2050, with different regional scopes, product choices, and sourcing strategies. Socio-economic changes and population growth projections were based on the Shared Socioeconomic Pathway 2 (SSP2). The model assessed impacts on GHG emissions, land use, biodiversity, food prices, food security, and agricultural input use. Additional scenarios explored the effects of efficient processing and land restoration in forest ecosystems. The model calculates prevalence of undernourishment using dietary energy availability, minimum dietary energy requirements, and the coefficient of variation of food distribution. Biodiversity impacts were assessed through the Biodiversity Intactness Index (BII). The study incorporates various assumptions, including those regarding processing efficiency of plant-based alternatives and the allocation of processing by-products.

The reference scenario (REF) projects growing food demand, increased ASF consumption, higher crop use, and rising agricultural environmental impacts (land expansion, nitrogen input, water use, GHG emissions, biodiversity loss) by 2050. In contrast, scenarios incorporating ASF substitution with plant-based alternatives show substantial reductions in environmental impacts. A 50% substitution reduces agricultural area, nearly halts forest loss, significantly decreases nitrogen use and water consumption, and lowers GHG emissions by 31%. Land restoration in forest ecosystems doubles this benefit, reaching 92% of estimated land sector mitigation potential. The restored area could substantially contribute to global land restoration targets (13-25% of the Kunming-Montreal Global Biodiversity Framework target by 2030). Biodiversity loss is more than halved. Regional impacts vary, with China contributing significantly to agricultural input reductions, while Sub-Saharan Africa and South America show the largest environmental gains. Beef substitution has the largest single impact, but synergistic benefits arise from replacing multiple ASFs. Processing efficiency impacts are small except at higher substitution rates. Increasing substitution beyond 50% provides little further deforestation reduction, but opens up opportunities for carbon sequestration through land restoration. The study notes that at higher substitution rates (90%), reduced demand for livestock can lead to lower productivity and increased emissions intensity.

The findings demonstrate the potential of large-scale dietary shifts to address climate and biodiversity goals. The study’s comprehensive approach, incorporating realistic recipe compositions within a dynamic global framework, strengthens the findings. The results show substantial GHG emission reductions, comparable to but larger than some prior research on limited substitutions. Land restoration emerges as a crucial complementary strategy for maximizing environmental benefits. The study highlights the uneven regional distribution of impacts, emphasizing the need for regionally tailored policies. Synergies between substituting multiple ASFs show that a holistic strategy is more beneficial than focusing on only one product. The study’s findings are consistent with ambitious climate mitigation and biodiversity conservation objectives.

Replacing 50% of ASFs with novel alternatives offers substantial environmental benefits. This is achievable with realistic ingredient compositions and a dynamic system-wide framework. Land restoration further amplifies these benefits, significantly contributing to global targets. Regional variations necessitate tailored policies. Future research could investigate broader economic impacts and strategies for ensuring a just transition for stakeholders in the livestock sector. This study provides compelling evidence for integrating novel plant-based alternatives into broader strategies for sustainable food systems.

The study's analysis is limited to a specific model, GLOBIOM, with inherent assumptions and limitations. It does not consider the full range of economic, social, and health consequences of the transition. The model uses pre-defined recipes and doesn't model the market development of novel alternatives or their potential price fluctuations, which could influence the adoption rate. Also, the analysis doesn't account for the potential substitution of animal fats, and only considers afforestation in former forest ecosystems. Finally, the impact of price declines on producers is not assessed in detail.