Following a sustainable diet is a win-win for your health and the planet, according to new research.
Scientists from the Harvard TH Chan School of Public Health in the USA have found that people who eat more environmentally sustainable food have a 25 per cent lower risk of death compared to those with a less sustainable diet.
A sustainable diet that is good for you, also known as a ‘planetary health diet’, includes whole grains, fruits, nuts, non-starchy vegetables, and unsaturated oils (such as olive oil). Starchy vegetables include beetroot, parsnips, peas and potatoes. This is in contrast to foods such as eggs and red and processed meats, which are regarded as less environmentally friendly.
The study involved over 100,000 participants in the USA, with a 30-year check-up period in which 47,000 of the participants died.
The findings, which were presented at the American Society for Nutrition’s 2023 conference in Boston, USA, show that the participants with a good planetary health diet had a reduced risk of all causes of death measured in the study. These included cancer, cardiovascular disease (which can cause heart attacks), infectious diseases, and neurodegenerative disease, such as dementia.
According to Linh Bui, the PhD candidate at Harvard who presented the findings, the research team combined the "best current scientific evidence" of the effect of different foods on both human health and the natural world,
Using this combined data, the scientists created a Planetary Health Diet Index, and gave the participants scores based on their diets. Using this, they assessed the relationship between the scores and the participants’ health outcomes.
“The results confirmed our hypothesis that a higher Planetary Health Diet score was associated with a lower risk of mortality,” said Bui.
The people with the highest Planetary Health Index scores had a 25 per cent lower overall risk of death than those with the lowest scores. When broken down into more specific causes of death, those with higher scores had a 15 per cent lower risk of death from cancer or cardiovascular disease, a 20 per cent lower risk from neurodegenerative disease, and a huge 50 per cent lower risk from respiratory diseases.
The environmental impact of the foods was assessed by factors such as water use, land use, pollution, and greenhouse gas emissions.
The researchers hope that the index can be used as a simple tool for policymakers and public health services to simultaneously improve human health and tackle the climate crisis.
However, they acknowledge that the index does not take into account certain challenges that people may have in following a sustainable diet, such as health conditions, religious restrictions, or socioeconomic availability of food. They hope that further research will address these barriers, as well as relationships between foods and diseases tailored to particular countries.
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