Résumé
BackgroundHuman evolutionary history indicates adaptation to an omnivorous diet including both animal and plant foods, with cultural and genetic adaptations following the Neolithic transition. While global consumption of animal-source foods has increased in the last decades, vegetarian and vegan diets have gained popularity in high-income countries for ethical, health, and environmental reasons. However, recent quantitative and qualitative changes in meat, dairy, fish, and ultra-processed products may contribute to a mismatch with ancestral diets. ObjectivesThis article synthesizes evidence for human adaptation to animal source foods, evaluates changes in contemporary diets, and assesses the nutritional adequacy and health outcomes of vegetarian and vegan diets across life stages, including vulnerable populations such as pregnant women, infants and children.MethodsThis narrative review integrates evolutionary biology, historical and contemporary dietary data, and evidence from recent studies, reviews and meta-analyses. The discussion considers nutrient composition, evolutionary mismatches, and potential health risks and benefits of plant-based diets, with attention to population specific considerations and supplementation strategies.ResultsEvolutionary data support human adaptation to omnivorous diet including animal-source foods alongside diverse plant intake. However, modern increases in processed meats, altered fatty acid profiles and environmental contaminants may contribute to maladaptation. Well-planned vegetarian and vegan diets are associated with lower BMI, improved lipid profiles and reduced risk of some chronic diseases. Without appropriate supplementation, they increase the risk of deficiencies, particularly vitamin B12, and potentially iron, zinc, calcium, vitamin D, omega-3 fatty acids, choline and taurine. In pregnancy and childhood, such diets can support normal growth and development when carefully planned and monitored.ConclusionsDietary quality, diversity, and nutrient adequacy rather than the mere presence or exclusion of animal products are central to long-term health. Both omnivorous and plant-based diets can align with human biology when based on minimally processed foods and adapted to life-stage-specific needs.