Mapping high-impact groups across dietary sustainability and nutrition

A sustainable food system requires significant dietary shifts. While understanding the diverse food habits across billions of consumers is important, current models do not distinguish consumer-level environmental footprints. Micro-data on food consumption (e.g., by gender and age) offers the potential to pinpoint high-impact and vulnerable consumer groups. We develop a globally harmonised model integrating individual food intake and supply chains to explore dietary footprints (e.g., climate, water and land) and dietary quality using the Alternative Healthy Eating Index (AHEI), across 70+ socio-demographic subgroups in 150+ countries. We find highly educated urban males aged 15–34 have the highest per capita emissions (median: 3.97 kg CO₂-eq/2,000 kcal, IQR: 2.96–5.96), with 65% of their diets being plant-sourced foods. Low education, rural females aged 35–54 have the lowest (2.39 kg CO₂-eq/2,000 kcal, IQR: 1.72–3.52), with plant-sourced foods comprising 74% of their diets. Adults aged 35–54 years and individuals with lower education see the lowest impacts per capita. Each 5% increase in the AHEI is associated with an 8.6% reduction in GHG emissions, a 4.9% reduction in water use, and an 8.7% reduction in land use. Our findings highlight the need for the use of micro-level intake data to deliver targeted and equitable dietary policies that focus on high-emission groups—such as young, urban, highly educated men—while supporting low-emission, nutritionally vulnerable populations.