The World Diet Initiative (WDI), introduced in the journal Nature Medicine in July 2026, seeks to document and study the world’s disappearing heritage diets before this dietary knowledge is lost—a project the research team described as “a race against time.”
“The dietary systems that could yield important insights into human metabolic and immune health are being transformed faster than they can be studied,” wrote the team of international experts in microbiome science, public health, gastroenterology, medicine and nutrition.
“The World Diet Initiative aims to close that gap, at least partially, to document heritage diets while they are still practiced, to investigate their biological effects and to build the coordinated scientific infrastructure needed to translate these insights into health benefits for diverse populations.”
What can be learned from studying heritage diets?
Heritage diets are traditional ways of eating shaped by a communities local foods, cultures, environments and history, with knowledge passed down through generations. Communities build these diets around foods that are grown or are available locally, normaling spanning grains, legumes, vegetables, fruits, nuts, seeds, meat, fish and fermented foods.
A heritage diet also captures how people prepare, preserve and eat those foods. Traditional practices such as fermenting, drying, smoking, soaking, sprouting and grinding can change the nutritional composition of foods and create new bioactive compounds. Seasonal eating, meal patterns, fasting and communal eating can also form an important part of the dietary tradition.
Over the past half-century, urbanization, economic development, and the globalization of food systems have fundamentally homogenized dietary patterns worldwide. Long-standing, locally embedded heritage diets are rapidly disappearing, replaced by highly homogeneous diets rich in saturated fat, sugar and industrially processed foods.
This rapid transition has driven a surge in non-communicable diseases like obesity and cardiovascular disease. The loss of these traditional diets is also reducing the world’s dietary diversity, removing a valuable “living laboratory” for researchers studying how different long-term diets influence human immunity, metabolism and the gut microbiome.
For the WDI research team, this highlights a clear need for systematic research into heritage diets, which represent complex, co-evolved systems shaped by local ecologies, traditional food processing and preservation practices, but whose health effects can vary considerably between populations.
“Heritage diets are not simply about bringing back the past,” said Carly Brown, scientific researcher at Radboud University Medical Center and co-first author on the Nature Medicine paper.
“Farming practices, soil and food varieties have changed so much that much of what our ancestors ate may no longer be possible to reproduce. Our aim isn’t to recreate entire diets but to identify and reintroduce specific foods, preparation methods and fermentation practices that have been lost—even small elements could have a significant impact on public health.”
Pillars of the World Diet Initiative
The WDI aims to capture biological, behavioral and cultural data from heritage diets, bringing researchers together through two complementary pillars:
- The World Diet Atlas (WDA) will provide an open-access global resource that systematically documents and characterizes heritage dietary systems using a standardized framework, recording ingredients, sourcing and preparation methods, alongside behavioral practices such as commensality, meal timing and fasting.
- The World Diet Project (WDP) will generate comparable biological evidence on how heritage diets affect human health to establish a federated, standardized multi-omics biobank linking dietary exposures with microbiome, immune and metabolic phenotypes.
Inspired by immune response research
The initiative grew out of several years of research into immune variation, including work by researchers at Radboud University in the Netherlands who set up the Human Functional Genomics Project in 2009.
The project investigated how genetic differences influence the human immune system and people’s responses to disease, with researchers collecting genetic and immune data from thousands of individuals and analyzing how specific genetic variants affected immune responses, such as the production of cytokines—proteins that help control inflammation in the body.
“Through that work, the one thing that came up time and time again as the most important reason for immune variation or immune health was diet,” Brown said.
“The findings prompted a broader question: If one heritage diet can have such significant effects on health, what could be learned from the thousands of traditional diets that exist around the world?”
Recent research by the same team examined how Tanzania’s traditional heritage diet affects the immune system. The dietary-switching study also published in Nature Medicine found that switching between a traditional Tanzanian diet and a Western-style diet produced marked changes in inflammation, metabolic pathways and immune function within just two weeks.
“The effects on inflammation, metabolic pathway dysregulation and actual immune cells not being able to fight infection when they were tested in the lab were just profound after two weeks,” Brown said. “That was the real spark of ‘there is something seriously significant here’.”
She noted that the work prompted the realization that if one diet in one community in Kilimanjaro could have such profound effects, thousands of traditional diets around the world might have similarly unique effects. Each has its own ingredients, practices and fermentation methods, which may interact with people’s genomes in different ways.
“There is an incredible amount still to discover—researchers have barely characterized any of it,” she said. “That’s when we thought this evidence is really critical—to safeguard traditional diets, to show policymakers and local people and communities how good these diets are for their health, and to add to the effort to conserve and preserve them.”
Designing a global research protocol
The team is now developing the WDI Blueprint Research Protocol, which will be freely available to researchers worldwide who want to study their own heritage diets.
Rather than conducting the research themselves, the team aims to facilitate and support researchers as they adapt adapt the protocol to their own needs and carry out the work themselves, Brown explained.
“It’s free to use for any researcher around the world who wants to do research on their heritage diet,” she said. “We don’t want to go and do everyone’s research for them. That’s not the ethos. It’s very bottom-up. We will facilitate and support, but please feel free to do it yourselves and adapt it as well.”
The blueprint will include different modules, such as microbiome analysis and immune-marker testing, allowing researchers to select the approaches most relevant to their questions.
By bringing these studies together, the initiative seeks to build a large, robust and consistent dataset that can generate comparable results across populations and provide stronger evidence for policy and impact than small individual studies.
From heritage diets to new health interventions
Brown noted that the project will help to identify specific foods, nutrients, combinations and chemical compounds that drive the health effects observed in different heritage diets.
“Inevitably, our research will produce a lot of these new discoveries and new leads,” she said. “With the right benefit-sharing model, keeping a focus on local evidence being used to support the health of local populations and making sure we’re not extracting from communities, we’d like to work to develop those into interventions or supplements, medicines—basically any way that we can convert that knowledge into improvements in health.”
The team has already begun planning a future innovation arm focused on discovering new molecules.
“That’s really exciting because there are so many undiscovered or never-before-researched chemicals in all of these foods that have never been looked at,” Brown said.
One arm of the recent research in Tanzania found that mbege, a traditional, mildly alcoholic fermented beer made from ripe bananas and sprouted finger millet, has strong effects on the microbiome and the fungal community of the gut.
“Off the back of that, a supplement company got in touch and they are now planning some clinical trials with a product formulated based on some of the strains found in this banana beer,” Brown said. “The next stage will be to show if it drives the same effects in a European population as it does in the local population.”
