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Planet-friendly foods can reduce your risk of mortality by 25 percent

In the pursuit of a healthier population and a healthier planet, a new study points to a compelling correlation between diet sustainability and human longevity. The research adds to a growing collection of evidence suggesting that planet-friendly foods offer a dual advantage for both personal health and the well-being of our environment. 

According to the study, led by the Harvard T.H. Chan School of Public Health, individuals who adhere to more environmentally sustainable diets have a 25 percent lower mortality rate compared to those who consume less sustainable diets.

These planet-friendly foods include staples such as whole grains, fruits, non-starchy vegetables, nuts, and unsaturated oils. On the contrary, foods like eggs and red and processed meats could pose detrimental effects to both environmental sustainability and human health. 

Environmentally conscious eating

The research implies that a shift towards more environmentally conscious eating habits could effectively lower one’s risk of mortality from various causes. Cancer, heart disease, respiratory ailments, and neurodegenerative diseases are included in this list, among others.

“We proposed a new diet score that incorporates the best current scientific evidence of food effects on both health and the environment,” said Linh Bui, a PhD candidate in the Department of Nutrition at Harvard T.H. Chan School of Public Health. She noted that the findings confirmed their hypothesis that a direct link exists between a higher Planetary Health Diet score and a reduced risk of mortality.

Bui will share these groundbreaking results at NUTRITION 2023, the flagship annual convention of the American Society for Nutrition, taking place from July 22–25 in Boston.

Planet-friendly foods

Current data highlights the potential health and environmental benefits associated with plant-based diets. They link with a diminished risk of chronic illnesses.

These include heart disease, colorectal cancer, diabetes, and stroke. At the same time, plant-based diets help mitigate detrimental environmental impacts including water use, land exploitation, nutrient pollution, and greenhouse gas emissions.

With their latest study, the research team sought to devise a simple, practical tool. The intention is to assist policymakers and public health professionals in strategizing initiatives for public health improvement. Concurrently, they hope to tackle the pressing issue of climate change.

“A sustainable dietary pattern should not only be healthy but also consistent within planetary boundaries for greenhouse gas emissions and other environmental parameters,” said Bui.

Planetary Health Diet Index

The research team developed the Planetary Health Diet Index (PHDI) after carefully reviewing existing research on the correlation between different food groups and health outcomes. 

The index, built upon the EAT-Lancet reference diet, considers the environmental impacts of food production practices. 

To determine the practical implications of their index, the researchers used it to analyze health outcomes in over 100,000 participants. The United States conducted two extensive cohort studies, and this was part of them. The data set included over 47,000 deaths during a follow-up period stretching from 1986-2018.

What the researchers learned 

The researchers discovered that the individuals in the highest quintile (or top one-fifth) for PHDI exhibited a 25% reduced risk of death from any cause when compared to those in the lowest quintile. 

Higher PHDI scores were linked with a 15% reduced risk of death from cancer or cardiovascular diseases. They also tie to a 20% reduced risk of death from neurodegenerative disease. Finally, studies show a remarkable 50% lower risk of death from respiratory diseases.

Further research is needed on planet-friendly foods

Despite these encouraging findings, Bui warned that the PHDI might not reflect the complex relationship between all food items and their connection to major diseases in all countries. 

There might be barriers such as specific health conditions, religious restrictions, or variations in food accessibility due to socioeconomic status or food availability that could hinder some individuals’ adherence to a sustainable diet. Future research could help explore and address these challenges.

“We hope that researchers can adapt this index to specific food cultures and validate how it is associated with chronic diseases and environmental impacts such as carbon footprint, water footprint, and land use in other populations,” said Bui.

These findings open a new chapter in our understanding of the connection between diet and health. The study emphasizes the importance of considering the environmental implications of our food choices.

More about sustainable foods

Sustainable foods are those produced, processed, and distributed in ways that not only have low environmental impact, but also contribute to social justice and economic stability.

They support long-term environmental balance, community resilience, and human health. Here are some key components of sustainable food:

Environmentally Friendly Production

This means practices that reduce environmental harm. It involves managing and conserving water, maintaining healthy soil, minimizing air, water, and climate pollution, and promoting biodiversity. Techniques may include organic farming, permaculture, agroforestry, and regenerative agriculture, among others.

Seasonal and Local

Eating foods when they are in season and grown locally can reduce the carbon footprint associated with food production and transportation. It also contributes to local economies and community health.

Minimally Processed

Highly processed foods often require more energy to produce and package. In addition, they often contain less nutritional value than whole foods. Sustainable diets encourage the consumption of whole, minimally processed foods.

Fair Trade and Fair Labor Practices

Sustainable foods should be produced under conditions that support farm workers’ rights and fair trade. This includes paying fair wages, providing good working conditions, and not exploiting labor.

Reducing Food Waste

A significant percentage of food is wasted globally. Sustainable food practices encourage reducing food waste through better food storage, creative use of leftovers, and composting organic waste.

Animal Welfare

In sustainable food systems, animals are treated humanely and are given a natural diet and environment where they can exhibit their natural behavior. This often results in higher quality and healthier animal products.


A sustainable diet also focuses on nutrition. It should provide all the necessary nutrients for healthy living. Foods that are nutritionally dense (i.e., high in nutrients and low in empty calories) are a key part of a sustainable diet.

Plant-Based Diets

Generally, plant-based diets are more sustainable than diets high in animal products because they use fewer resources and create fewer emissions. This doesn’t necessarily mean vegan or vegetarian, but rather a diet higher in plant foods like vegetables, fruits, whole grains, legumes, seeds, and nuts.


Consuming a variety of foods can be good for both personal health and the health of the planet. A diverse diet can support diverse ecosystems, which are generally more resilient to environmental changes.

Sustainable food systems also include the people who eat the food, so education, food culture, and community involvement are also key components.

They are often described as “short supply chains”, where fewer steps between the producer and consumer can lead to less waste, fewer emissions, and a better connection between people and their food.

It’s important to note that sustainable food systems require systemic change, not just individual action. This includes changes in government policy, agricultural subsidies, corporate practices, and global trade rules.


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