Many diets for many people: planetary health diets and their health and environmental impacts at global, regional, national, and demographic levels

Without dietary changes towards healthier and more sustainable diets, there is little chance of addressing the growing burden of non-communicable diseases, avoiding dangerous levels of climate change, and staying within key planetary boundaries that define a safe operating space for humanity. Global reference values for healthy and sustainable eating exist, but consistent adaptations to local contexts are limited, which impacts food-related planning and decision-making. Here we develop a diverse set of “planetary health diets” that are adapted to the nutritional needs and preferences of populations at global, regional, national, and demographic levels. The set includes distinct dietary patterns (flexitarian, pescatarian, vegetarian, vegan) that differ across countries, age groups, and sexes. Using impact assessments, we show that adoption of these diets would be associated with substantial improvements in nutritional adequacy and simultaneous reductions in diet-related mortality and environmental resource demand, in each case across a wide range of regional and demographic scales. Our findings also indicate large differences to current diets, suggesting the need for dedicated initiatives and support for dietary change. We integrated the estimates of food intake and the associated impacts into interactive analysis tools to facilitate dietary planning and decision-making across dietary preferences at regional and demographic levels.