Switching to diets that contain no more than three meat meals each week could prevent around 45,000 early deaths and save the NHS £1.2 billion each year - as well as helping to tackle climate change and curb deforestation, according to a new Friends of the Earth report.
Researchers from Oxford University analysed the health implications of a range of dietary options and concluded that lower-meat diets could cut deaths from heart disease by around 31,000, deaths from cancer by 9,000 and deaths from strokes by 5,000 each year.
The report also highlights how factory farming and processing of meat has made it less healthy, with an average supermarket chicken today containing 2.7 times as much fat as in 1970 and 30 per cent less protein.
Its release comes ahead of a key vote in Parliament on the Sustainable Livestock Bill in November. If passed, the new law should see the government recommending healthier meat-based diets and changing the way food production is funded through subsidies paid for by taxpayers.
Friends of the Earth say that current levels and methods of meat production are driving wildlife loss in South America where rainforests are being cleared to grow animal feed and rear cattle for export to Europe.
"We don't need to go vegetarian to look after ourselves and our planet - but we do need to cut down on meat,” said Craig Bennett, Friends of the Earth's Director of Policy and Campaigns.
He added, "While the Government has ignored the environmental impact of high meat and dairy consumption, it can't ignore the lives that would be saved by switching to less and better meat".
Mike Rayner of the Department of Public Health at the University of Oxford said that the research “demonstrates the clear health benefits of cutting down on meat and dairy in the UK and quantifies this more comprehensively than ever before."
Bennett accused the government of funding “damaging factory farms” and encouraged supporters to lobby their MPs to vote for the Sustainable Livestock Bill on 12 November.