Key points • Animal-source foods (ASFs) are major drivers of negative environmental impacts and health risks, contributing to greenhouse gas emissions, extensive planetary resource use, non-communicable diseases, zoonoses, and antimicrobial resistance. • ASF alternatives, including plant, microbe, fungi, insects and cultivated cell products hold promise for diversifying protein sources, but their health, nutritional, and safety implications remain insufficiently evaluated. • The transformative potential of ASF alternatives depends on comprehensive assessment of their health, environmental, and social impacts, alongside policies that ensure sustainable and just food systems. Contrary to their intended purpose of feeding people, current food systems are harming both human health and the planet (Global Panel on Agriculture and Food Systems for Nutrition, 2020). Food production accounts for 24% of global greenhouse gas (GHG) emissions, uses 68% of freshwater resources, and occupies 37% of land (WRI, 2019). Food demand is projected to rise by 35-56% by 2050, driven by population growth (Van Dijk et al., 2021). Among different food groups, animal-source foods (ASFs) are the ones with the greatest environmental impact. Their overconsumption, particularly red and processed meat, is also associated with higher risks of non-communicable diseases (NCDs). Intense animal farming further contributes to health risks, including through increased risk of zoonotic disease emergence and the development of antimicrobial resistance (WHO, 2023). Proposed solutions to reduce the impact of food systems on planetary boundaries include: (i) dietary shifts to plant food, (ii) technological innovations, and (iii) food waste reduction (Springmann, 2018). Dietary shifts Increasing the proportion of plant-based foods in diets means adopting patterns long practiced across many cultures. The most urgent shift is needed in populations consuming excessive amounts of ASFs. While there is likely no minimum intake of meat, dietary guidelines recommend between 100-500 g/week (WHO, 2023), with flexitarian diets suggesting even less (Willett et al., 2019). Yet in some high-income countries (HICs), average consumption exceeds 700 g/week. Protein requirements are estimated at about 50g/person/day, but intake in many HICs is roughly double. These trends are largely shaped by cultural preferences and a food environment that supports such dietary patterns. Alternatives to animal source foods To replace ASFs while mimicking their qualities, a range of alternatives has been developed using plants, microbes, fungi, insects, or cultured animal cells and as outlined in greater detail in the Frontiers in Science lead article by Kaplan and McClements (2025). These products require fewer resources (land, water, energy) and emit fewer GHGs than conventional animal products, though outcomes depend on specific processing methods. The use of alternatives to ASFs may also address health concerns, as it is possible to alter the content of nutrients that may be responsible for negative health effects, such as lipid composition. However, the rapid expansion of alternative products underscores the need for deeper understanding of their health impacts, assessed across multiple dimensions including food safety and chronic disease risk. For example, chemical and microbiological contaminants, toxic compounds, and allergens must be monitored at every stage of production. FAO and WHO have begun to map relevant hazards in cultured meats (FAO & WHO, 2023). Nutrient composition is a primary focus of developers, for instance, with particular emphasis on protein digestibility and quality (e.g., PDCAAS), micronutrient content, and antinutritional factors. Yet critics of the reductionist approach (nutritionism) stress the need for holistic assessments, that consider the overall dietary pattern to which foods contribute as well as their cultural, social and economic impacts. Physiological and health impacts Comprehensive evaluations are still lacking on how alternatives to animal proteins affect metabolic pathways (lipids, protein, glucose, and mineral status and balance), satiety, the gut microbiome, or cell replication. Few clinical studies have assessed the impact of alternatives to ASFs on human health. Exposomic approaches, which consider the combined effects of natural and manufacturing-related compounds, could help enable more robust safety assessments. The discussion on ultra-processed foods (UPFs) is particularly relevant. While some alternatives to ASFs (e.g., tempeh) are modifications of traditional preparations, many others involve complex processes and would be classified as UPFs under the Nova system (Monteiro et al., 2018). UPFs typically consist of ingredients extracted from their original food matrices, combined with additives to enhance palatability. In fact, they are often designed to be hyperpalatable and, therefore, prone to overconsumption. Consumption of UPFs has been linked to adverse health effects via multiple mechanisms, including nutrient profiles, altered food matrices (e.g., easier chewing and faster nutrient absorption), microbiome disruption, exposure to additives and packaging materials, and high palatability leading to overconsumption (Lane et al., 2024). Growing public concern has already contributed to the establishment of public policies aimed at reducing UPF consumption (Popkin et al. 2021), and manufacturers of alternative proteins are aware of this sensitivity. Social and economic dimensions Concerns also extend beyond health. Greater reliance on highly processed alternatives may reduce the role of fresh, locally produced foods. This has social and economic implications, accelerating the concentration of food production in the hands of few global corporations prioritizing profits over peoples' health and sustainability. To fully realize their value, alternative proteins must therefore address not only nutritional and safety concerns, but also broader social and economic impacts. As illustrated by Kaplan and McClements (2025), hybrids products, combining modern technological ingredients with traditional plant and animal components, represent one pathway forward. For example, plant-derived proteins may be paired with animal cells to provide a source of vitamins, minerals and bioactive compounds while maintaining favorable nutrient profiles. Environmental assessment and policy implications Environmental impacts also require clearer evaluation. Life cycle assessments must capture the full range of inputs and outputs to provide realistic comparisons with conventional foods and with dietary strategies emphasizing minimally processed plant-based foods (whole grain cereals, fruit, vegetables, nuts and legumes). Future scenarios should also account for changing environmental conditions that will affect both crop and animal productions. Ultimately, the role of alternative proteins must be considered within comprehensive national food policies. They may be particularly valuable in contexts where ASF production is constrained (e.g., in a country with little territorial extension such as Singapore) or where overconsumption must be curbed for health and sustainability (e.g., in HICs). A risk-benefit assessment approach is needed, integrating product design, dietary context, and broader societal impacts. Initiatives aimed at democratizing the production of alternative ASFs (e.g., New Harvest) or promote decentralized/localized manufacturing may help ensure more equitable outcomes. Conclusion Alternative proteins are a valuable resource to be considered as part of integrated policies to build healthier, more sustainable, and just food systems. However, this potential can only be realized through comprehensive research addressing nutritional, physiological, safety, environmental, and socio-economic dimensions, alongside careful integration into food policy.
Francesco Branca (Tue,) studied this question.
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