Healthier food choices almost always benefit the environment, according to a sophisticated new study.

The research was published in the journal Proceedings of the National Academy of Sciences.

The analysis assessed the health and environmental impacts of 15 foods common in Western diets and found fruit, vegetables, beans and wholegrains were best for both avoiding disease and protecting the climate and water resources.

The study found that eating more red and processed meat causes the most ill health and pollution.

Using data from other studies on the diets and health outcomes of tens of millions of people they calculated the health impact of eating one extra portion of each food on heart disease, stroke, type 2 diabetes and colorectal cancer.

The environmental harm for each food, from greenhouse gases to water use to pollution was also calculated.

The study found that producing unprocessed red meat had the highest impact for all environmental indicators and was many times worse than pulses.

The researchers said foods with medium environmental impacts or not significantly associated with ill health, such as refined grain cereals, dairy, eggs and chicken, could help improve health and reduce environmental harm if they replaced foods such as red meat.

Michael Clark at the University of Oxford, who led the research, told The Guardian: “Continuing to eat the way we do threatens societies, through chronic ill health and degradation of earth’s climate, ecosystems and water resources.

“Choosing better, more sustainable diets is one of the main ways people can improve their health and help protect the environment.”