Plant-based meat alternatives can support reductions in agricultural land expansion and greenhouse gas emissions but entail micronutrient trade-offs.

Plant-based meat alternatives (PBMAs), designed to mimic the sensory properties of meat, may help reduce animal-sourced protein consumption and support a shift towards plant-based diets. Here we integrated PBMAs into a land-use model to assess their effects on nutrition, greenhouse gas emissions and food system sustainability. PBMA adoption not only substantially reduced agricultural land expansion and greenhouse gas emissions from the agriculture, forestry and other land use sector but also increased risks of micronutrient inadequacy. Across regions, PBMA diets exhibited diminishing marginal returns. Replacing ruminant meat alone achieved nearly half of the potential emission reductions while incurring relatively small nutritional costs. By contrast, broader substitution of livestock products delivered additional environmental benefits but markedly increased micronutrient deficiencies. Targeted policy support, sustainable land management and improved PBMA formulations will be essential to ensure equitable dietary transitions and progress towards global climate and sustainability goals.