By eating less meat and more fruit and vegetables, the world could avoid several million deaths per year by 2050, cut planet-warming emissions substantially, and save billions of dollars annually in health care costs and climate damage, researchers said.

A new study, published in the Proceedings of the National Academy of Sciences of the United States of America, is the first to estimate both the health and climate change impacts of a global move toward a more plant-based diet, they said.

Unbalanced diets are responsible for the greatest health burden around the world, and our food system produces more than a quarter of greenhouse gas emissions, said lead author Marco Springmann of the Oxford Martin Programme on the Future of Food.

Adopting a diet in line with the global guidelines could avoid 5.1 million deaths per year by 2050, while 8.1 million fewer people would die in a world of vegans who do not consume animal products, including eggs and milk.

When it comes to climate change, following dietary recommendations would cut food-related emissions by 29 percent, adopting vegetarian diets would cut them by 63 percent and vegan diets by 70 percent.

Dietary shifts could produce savings of US$700 billion to US$1 trillion per year on health care, unpaid care and lost working days, while the economic benefit of reduced greenhouse gas emissions could be as much as US$570 billion, the study said.