Researchers launch global initiative to study disappearing heritage diets
The world's ‘heritage’ diets could hold vital clues to better health. Writing in Nature Medicine, researchers from 12 countries have launched the World Diet Initiative, a global effort to document and study these diets before this knowledge is lost.
People around the world have practised distinct diets for thousands of years. Maasai communities in East Africa are known for diets rich in animal products such as milk, meat and blood. In Ethiopia, diets are largely plant-based, featuring pulses, vegetables and grains, often fermented. Indian meals draw on a rich array of spices, while across the Pacific, fish, taro and coconut are commonplace.
These heritage diets have developed over generations, shaped by the foods available in the local environment and the ways they are prepared. In some communities that still follow heritage diets, chronic illnesses such as diabetes and cardiovascular disease have historically been less common.
Dietary diversity is disappearing fast
Heritage diets around the world are being replaced by uniform 'Western-style' diets featuring the same industrially processed foods. As these diets disappear, so too does a precious opportunity to understand how they shape human health.
The World Diet Initiative aims to close this gap through two components:
- The World Diet Atlas will map heritage diets worldwide, detailing the foods and how they are sourced, prepared and eaten. It will be a freely available resource for researchers, policymakers and communities.
- The World Diet Project will study the biological effects of these diets, using consistent methods so findings can be compared across populations.
The initiative will operate as a global consortium. Local partners will lead research and retain ownership, with findings shared responsibly with researchers around the world.
Changes within two weeks
Recent work by some of the initiative's founders offers a glimpse of how studying heritage diets can reveal new insights into how foods shape health.
In a trial in the Kilimanjaro region of Tanzania, men who swapped their local heritage diet, rich in legumes, whole grains and fermented foods, for a processed, Western-style diet showed increased inflammation and other biological changes linked to chronic disease within just two weeks.
Those who switched the other way, or drank a traditional fermented millet-and-banana drink, showed changes in the opposite direction, including reduced inflammatory markers.
Not a blueprint for healthy eating
The researchers stress that the initiative is not a nostalgic call to return to past ways of eating, nor a claim that heritage diets are always healthier. The point is that these diets act on the body, the immune system, metabolism and microbiome, in strikingly different ways, and each has something to teach us. "These diets are not a blueprint for healthy eating, but they are biologically and culturally unique. Food influences our health in many ways and plays an important role in preventing disease," says Quirijn de Mast of Radboud university medical center, co-lead of the initiative. "With the World Diet Initiative, we are now building the infrastructure to capture this knowledge and translate insights from heritage diets into health benefits for people worldwide - from preventing chronic diseases to better understanding how nutrition shapes immune function and vaccine responses.”
Journal
Nature Medicine
Method of Research
Meta-analysis
Subject of Research
People
Article Title
Studying vanishing dietary diversity before it is lost: the World Diet Initiative
Article Publication Date
15-Jul-2026
Shift to healthy, sustainable diets would reshape global agriculture
London School of Hygiene & Tropical Medicine
Following recommendations to shift to healthier diets, improve farm productivity and halve food waste, could reduce global agricultural land use by up to 6% by 2050 and lead to a 42% decline ($630 billion) in global livestock production value compared to 2020.
Implementing the changes by 2050 would also lead to an estimated 70% ($274bn) decrease in the production value of ruminant animals (beef cattle, sheep, and goats) and 400 million fewer ruminant animals globally compared to 2020. In contrast the global value of vegetable, fruit, nut and legume production would increase by 57% ($890bn).
The findings come from a new analysis published in Nature by researchers from the London School of Hygiene & Tropical Medicine (LSHTM), Cornell University, and 10 modelling teams that looked at the implications of implementing a 2025 EAT-Lancet Commission style food systems transformation.
The 2025 EAT-Lancet Commission report found that if people around the world switched to healthy diets it would result in 15 million fewer premature deaths per year. Previous research estimated the hidden costs of current global food systems at $10-$20 trillion annually, with the majority of these costs linked to unhealthy diets.
The new analysis shows that following the 2025 EAT-Lancet Commission recommendations could also see agriculture related net-CO2 emissions from land-use change fall by 85% by 2050 compared to 2020 levels.
Dr Matt Gibson, lead author, who began the work at Cornell University before joining the London School of Hygiene & Tropical Medicine (LSHTM), said: “Transforming food systems would deliver enormous potential benefits to our health and the environment but, as our results make clear, they would also lead to fundamental changes to global agriculture and affect the lives of millions of farmers and food producers.
“Rather than using these results as an excuse for inaction it’s critical that governments rise to the challenge and make difficult decisions for the good of our health and the planet. This means confronting powerful groups that profit from the status quo and a global food system that currently fails both those who produce our food and those who should be nourished by it.”
Daniel Mason-D’Croz, study co-author from Cornell University, said: “We should consider these scenarios not as a forecast of what will happen, but as a useful early guide of where challenges and opportunities may arise. Which sectors would need to contract, and which would need to expand. A transformation of this magnitude cannot begin in 2050. Foresight modelling like that highlighted in this study is a valuable tool to inform actions today for more sustainable, healthy, and just food systems tomorrow.”
The study suggests the impacts of food transformation on agriculture at a regional and national level would vary: overall US agricultural production value would decrease by 21% ($76bn) by 2050 compared to 2020, but within this US crop production value would increase by 20% ($40bn) while livestock production value would decrease by 73% ($116bn).
In India the picture is different: overall Indian agricultural production value would increase by 46% ($198bn) by 2050 compared to 2020. Within this Indian crop production value would increase by 65% ($208bn) while livestock production value would decrease by 8% ($10bn).
European agricultural production value would decrease overall by 35% ($190bn) by 2050 compared to 2020. Within this, European crop production value would decrease by 8% ($22bn) while livestock production value would decrease by 66% ($168bn).
The study assumed a costless consumer preference shift toward healthy diets (i.e. people change their behaviour to demand healthier diets). In reality, the authors say there are challenges to changing consumer behaviour including questions of accessibility and affordability, as well as engaging with broader food cultures and individual tastes that all contribute to dietary choices. The scenarios explored in the study represent one of many alternative futures. More work is needed to develop and examine radically different scenarios.
The authors say that taking bold policy decisions now can help to support vulnerable groups produces and consumers in a world that transforms towards healthier, more sustainable diets.
Journal
Nature
Method of Research
Computational simulation/modeling
Article Title
'Food systems transformation would reshape global agriculture'
Article Publication Date
15-Jul-2026
Healthier, more sustainable diets would reshape global agriculture; a new study shows by how much
There is a clear need to shift towards healthier and more sustainable food systems. According to the 2025 EAT-Lancet Commission Report, the global adoption of a flexitarian Planetary Health Diet could prevent around 15 million premature adult deaths per year. Today, food systems account for around one third of global anthropogenic greenhouse gas emissions, and are the main driver of five planetary boundary transgressions. At the same time, one third of all food is lost or wasted, while half of the world’s habitable land is used for agriculture – mostly for livestock and animal feed.
To explore the potential impacts of a food system transformation, researchers used ten global food system models to compare a “business-as-usual“ scenario until 2050 with a “transformation scenario” characterised by healthy diets, improved agricultural productivity, and halved food waste.
Hermann Lotze-Campen, PIK research department head and co-author, said: “Our study shows that continuing on the current path is the more expensive option. Providing healthy diets for a growing global population by 2050 would maintain the overall value of agricultural production near 2020 levels, while simultaneously reducing environmental and health costs compared to business-as-usual.”
Transformation would reduce global agricultural land use by 9 percent compared to business as usual
In all models, the business-as-usual scenario leads to increased animal numbers, larger harvested areas, higher production levels and greater environmental impacts like greenhouse gas emissions and nitrogen fertilisation. Under the transformation scenario, however, a larger share of agricultural products would be used directly for food, and less for animal feed. The transformation scenario also projects less meat, dairy, cereal and sugar crop production, reduced animal numbers, and lower pressure on land resources, lower production costs and producer prices in these sectors relative to business-as-usual.
Lead author Matt Gibson, Research Fellow at the London School of Hygiene and Tropical Medicine, who coordinated the study while at Cornell University, said: “Across all the models we employed, a transformation could reduce global agricultural land use by 9 percent and livestock production value by 60 percent by 2050, relative to business as usual, with total agricultural output reduced by 17 percent, mostly from livestock changes. These reductions are partly offset by growth in other sectors, with the economic production value of vegetables, fruits, nuts and legumes projected to increase by a median of 23 percent.”
Net CO₂ emissions from agriculture-related land-use change would decline by 76 percent
These production trajectories would have far-reaching implications for the political economy of global food systems. While the adverse effects are often concentrated, for example in livestock-oriented rural economies, the benefits for public health and the environment are more widely distributed. In fact, net CO₂ emissions from agriculture-related land-use change would decline by 76 percent by 2050 under a transformation scenario, compared to business as usual, while direct non-CO₂ greenhouse gas emissions from agricultural production would fall by one third.
“While the environmental and health opportunities are huge, managing structural challenges within the agricultural sector will require coherent food and agriculture policies and inclusive stakeholder dialogues,” said PIK scientist Felicitas Beier, also co-author of the study.
The authors conclude that the scale of change implied by a food system transformation calls for commensurate policy ambition, and that bold decisions in the present can help support those who could be adversely affected by the transition while maximising the benefits of a transformed food system.
Article:
Gibson, M., Sundiang, M., Mason-D’Croz, D., Diniz Oliveira, T., Beier, F., Benavidez, L., Bos, A., Chepeliev, M., Doelman, J., Dunston, S., Fujimori, S., Hasegawa, T., Havlik, P., Hristov, J., Jägermeyr, J., Kozicka, M., Kuiper, M., Kyle, P., de Lange, T., Bodirsky, B. L., Lotze-Campen, H., Luchtenbelt, H., Chen, D. M.-C., Mishra, A., Müller, C., Nelson, G., Palazzo, A., Perez Dominguez, I., Popp, A., Sands, R., Springmann, M., Stehfest, E., Sulser, T. B., Takahashi, K., Tassinari, G., Thom, F., Thornton, P., Tsuchiya, K., van Zeist, W.-J., van Meijl, H., van der Mensbrugghe, D., Van Vuuren, D., van Zanten, H. H. E., Weindl, I., Wiebe, K., Zhao, X. & Herrero, M., (2026): Food systems transformation would reshape global agriculture. Nature. DOI: 10.1038/s41586-026-10775-2
Journal
Nature
Method of Research
Computational simulation/modeling
Subject of Research
Not applicable
Article Title
Food systems transformation would reshape global agriculture
Article Publication Date
15-Jul-2026
Ketogenic diets may increase cancer risk in the small intestine
Massachusetts Institute of Technology
- Researchers found that mice on a ketogenic diet were more likely to develop tumors of the small intestine than those on a control diet.
- Additional studies revealed that ketone bodies did not play a role in tumor development; tumor growth was driven by how intestinal cells burn dietary fat for energy.
- Surprisingly, the same ketogenic diet that promoted tumors in the small intestine had the opposite effect in the colon.
CAMBRIDGE, MA -- A high-fat, low-carbohydrate diet, also called a ketogenic diet, can help some people lose weight by forcing their bodies to burn fat for fuel instead of sugar.
In recent years, scientists have been exploring how this type of diet might affect other aspects of health and disease, including cancer. While some research has shown that the diet may protect against the development of colon cancer, a new study by MIT researchers suggests that in the small intestine, a ketogenic diet may increase the risk of cancer.
“Ketogenic diets have distinct effects on different tissues even within the gastrointestinal tract. I think the message here is that we need to be very careful in generalizing the effects that these diets can have, because what might be beneficial for one tissue may be detrimental for another tissue,” says Omer Yilmaz, director of the MIT Stem Cell Initiative, an associate professor of biology at MIT, and a member of MIT’s Koch Institute for Integrative Cancer Research.
Yilmaz is the senior author of the study, which appears today in Nature. MIT postdocs Jessica Shay and Fangtao Chi are the lead authors of the paper. Researchers from the labs of Alex K. Shalek, director of MIT’s Institute for Medical Engineering and Science, and Matthew Vander Heiden, director of the Koch Institute, also contributed to the study.
Diet and cancer
Ketogenic diets, originally developed in the 1920s as a way to treat epilepsy, have been adapted in the past few decades as a strategy to lose weight or increase lifespan. The diet comprises a high percentage of fat, low percentage of carbohydrates, and normal or reduced amounts of protein.
This type of diet forces the body to burn fatty acids for energy in place of carbohydrates such as glucose. Burning these lipids produces ketone bodies — primarily β-hydroxybutyrate (BHB) and acetoacetate — as byproducts of fatty acid metabolism. These ketone bodies are also generated when people fast or follow very low-calorie diets, which force the body to burn its own fatty stores.
A 2022 Nature study suggested that ketogenic diets have a protective effect against colon cancer and that BHB — the most abundant ketone body — is responsible for this effect. In the new Nature study, the MIT team wanted to explore whether ketogenic diets might have a similar protective effect in the small intestine.
The researchers fed mice who were genetically predisposed to developing intestinal cancer either a ketogenic diet, a control diet, or a high fat/high calorie diet. They found that mice on a ketogenic diet were more likely to develop tumors of the small intestine than those on a control diet. While they did not become obese, mice on the ketogenic diet developed tumors at rates similar to or even higher than those of mice on an obesogenic high fat/high calorie diet.
Additional studies revealed that ketone bodies did not play a role in tumor development. Instead, tumor growth was driven by how intestinal cells burn dietary fat for energy — a metabolic pathway called fatty acid oxidation. This pathway activates a family of proteins called PPARs, which signal stem cells to multiply more rapidly, increasing the chance that some become cancerous.
This stem cell proliferation can be beneficial in certain situations, such as when the intestinal lining needs to be repaired after illness or injury. However, too much proliferation can tip cells toward becoming cancerous.
“Having more stem cells means that when you injure the small intestine, it can repair itself better, but the downside is that having more active stem cells can lead to tumor formation,” Yilmaz says.
Opposite effects
Surprisingly, the same ketogenic diet that promoted tumors in the small intestine had the opposite effect in the colon. The researchers found, similar to the earlier Nature study back in 2022, that a ketogenic diet suppressed the development of colon tumors. However, the new findings suggest that ketone bodies are not responsible for this protective effect.
“Given how much attention has been paid to ketone bodies like BHB, both as a commercial health trend and in recent high-profile studies suggesting BHB suppresses colon cancer, we fully expected them to be the direct drivers. Instead, our experiments in genetically engineered mice revealed that these molecules are essentially metabolic bystanders. The real surprise is that tumor acceleration is driven entirely by how stem cells process and burn the heavy influx of dietary fat itself,” Yilmaz says.
The researchers now hope to further study why ketogenic diets have such different effects in the colon and the small intestine. As ketogenic diets continue to gain popularity, understanding these tissue-specific effects will be critical for guiding their use, the researchers say.
“The deeper question is why the same diet has opposite consequences in two adjacent parts of the gut. That is what we are working to understand next,” Chi says.
The findings carry practical implications. Because the diet’s effects — both the tumor acceleration in the small intestine and the protection in the colon — are driven entirely by fat metabolism rather than the ketones themselves, commercial ketone supplements or drinks would not be expected to mimic either the risks or the benefits discovered in this study. This may be especially relevant given that small intestinal tumors have been rising in incidence in recent decades, with the greatest impact on patients with inherited conditions that predispose them to intestinal cancer, such as familial adenomatous polyposis.
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The research was funded, in part, by the National Institutes of Health, a Pew-Stewart Trust scholar award, the Kathy and Curt Marble cancer research award, a Koch Institute-Dana Farber/Harvard Cancer Center Bridge project grant, the American Federation for Aging Research, the MIT Stem Cell Initiative, a Damon Runyon Postdoctoral Research Fellowship, and the Koch Institute Support (core) grant from the National Cancer Institute.
Journal
Nature
Subject of Research
Animals
Article Title
Ketogenic diet mediates intestinal tumorigenesis through lipids not ketones
Article Publication Date
15-Jul-2026
