Food systems bring society and environment into our guts through the different farming, herding, foraging, processing, buying, cooking and eating practices. These practices shape our gut microbiome and its capacity to harvest energy and nutrients from the food. As such, our human and gut microbiome’s health depends on the health of food systems and environments, as reflected in the notions of Planetary Health and One Health. The organization of society and socio-cultural practices also shape which food enters our bodies and thereby take part in affecting nutrient intake and the gut microbiome. In the EATWELL project, we have therefore developed an integrated approach to the study of food systems and how they shape our bodies, including microbiomes, in ways that are situated in local contexts to contribute to the sustainable food systems for health agenda. We do so in a radical interdisciplinary way and deploying Bhutan as an informative, unique, and critical case, aiding precisely in teasing out the situated nature of human (micro)biologies as shaped through localized food systems. EATWELL consists of two main phases. In the first anthropological phase, we study the socio-culturally influenced food-related activities that transform natural resources into food, such as production, cooking and eating. In the second nutrition/microbiome phase, we study how these eating habits translate into nutrient intake and affect the gut microbiome. Since the start of the project, we have been studying key aspects on cultivation, cow and yak herding, foraging, buying, cooking, and eating. We have observed how these practices vary according to everyday life and ritual events, traditional and biomedical practices, as well as gender, age, socio-economic status and the environment. In 2023 and 2024, the anthropologists on the team have conducted fieldwork studying food systems in 7 sites across Bhutan for comparative purposes. Our preliminary findings have shown a surprisingly large variation in food habits and systems. They also have clearly demonstrated the importance of seasons, environments, and socio-cultural aspects in explaining these large variations. Simultaneously and based on these preliminary observations, we have designed the second phase of the project. This consists of two parts and will be carried out in 3 of these sites. In the first cross-sectional part, we will collect 1000 stool samples, each combined with a dietary recall and a nutrition/microbiome survey where we predominantly inquire about food related activities that are known or hypothesized to affect nutrient intake and the gut microbiome. 1000 participants will be recruited from two remote areas and the capital city of Thimphu where we focus on the 1st and 2nd generation migrants coming from the former. In this way, we can observe long-term evolution over generations of nutrient intake and the gut microbiome when people migrate to a radically different food environment. The second longitudinal part is conducted among 60 participants and consists of the same method but is repeated 10 times per person during one year. This will enable us to observe seasonal and activity-related variations in nutrient intake and the gut microbiome. The methods in EATWELL are radically interdisciplinary, involving ethnography, dietary recalls, stool sample collection, nutrition/microbiome surveys, metagenomic shotgun sequencing and bioinformatics to determine associations between socio-cultural food practices, nutrient intake and the gut microbiome as they evolve throughout seasonal variation and long-term evolution through migration. The project has the following overall aim: Develop an integrated approach to food systems that consider its different parts and their intricate entanglement. For this, we aim to 1) demonstrate how nutrition and the gut microbiome are associated with socio-cultural practices, 2) critically assess the universalist and biased assumptions of a large set of biological, biomedical, and nutritional sciences which exert a dominant influence in current approaches to food systems, 3) establish a mutually enriching conversation between the Buddhist-informed Bhutanese approaches to environment, food systems and health through GNH, and the global approaches to sustainable food systems for health as well as One Health and Planetary Health, 4) develop a radical interdisciplinary study program of food systems which advances knowledge about the intricate interplay between society, environment, food, nutrition and gut microbiome such that a situated understanding of food systems and health can be developed in a culture-sensitive way, 5) craft an integrated model for food system development that unites concerns for environmental sustainability, culture sensitivity, nutritional adequacy, gut microbiome, and health by engaging stakeholders and relevant actors and end-users in Bhutan and that can be replicated and adapted in different contexts.