A new study published in Nature Food introduces the MATILDA (Micro-Macro Assessment Tool to Identify Low-impact Dietary Actions) database, which provides a comprehensive analysis of how nutritional quality and environmental impacts of diets vary within populations across 165 countries, according to a Jul. 24 announcement.
The MATILDA database combines individual dietary surveys with country-level food supply chains and population data, offering policymakers detailed evidence beyond national averages. The study found that the highest-impact diets produce almost double the greenhouse gas emissions compared to the lowest-impact diets. Additionally, every 5% improvement in diet quality—measured by the Alternative Healthy Eating Index—was associated with a 7.7% reduction in diet-related greenhouse gas emissions, as well as lower water and land use. Diets higher in plant-based foods were consistently linked to lower environmental impacts.
Researchers said that factors such as location, education level, income, and broader social and environmental contexts influence people's dietary patterns more than personal choice alone. Recognizing these differences can help develop food policies that better reflect real-world conditions.
Dr. Oliver Taherzadeh from Leiden University said, "MATILDA connects what's on our plate to global environmental consequences. We achieve this by linking group-level dietary patterns to a macroeconomic model which captures their impact within and beyond national borders. To date, macroeconomic food system models have overlooked national-level differences in food consumption patterns and integration of food supply chain data into country case studies has been piecemeal. We try to bridge this gap and in doing so manage to pinpoint the high-impact and vulnerable consumer groups otherwise hidden by dietary food modelling and policy. This enables sustainable dietary policy to be more targeted, fair and effective."
Dr. Hongyi Cai from Leiden University said, "There is no one-size-fits-all when it comes to sustainable and healthy diets. When we benchmark the population against the actual diets they follow, food system impacts become more accountable, health inequalities become more explicit, and differentiated needs become more clear." Professor Paul Behrens from Oxford Martin School at University of Oxford said, "People don't make food choices in isolation. What we eat is shaped by where we live, what we can afford and what is available to us. We've entered an era where food policy can become much more evidence-based. Instead of treating entire populations as though they eat the same foods, we can now identify where interventions are likely to have the greatest benefit while making sure vulnerable groups aren't left behind."
The paper outlines possible policy responses such as public information campaigns, supermarket incentives for healthier choices, taxation measures or regulation, but concludes that uniform interventions are unlikely to be sufficient due to differing dietary patterns within populations.
