The initiative called Meat Free Monday is being fronted by the nutritionist Rosemary Stanton and the TV chef Janella Purcell and has received the backing of the entrepreneur Sir Richard Branson.

According to a study by the Australian Institute of Health and Welfare, fewer than one in 10 Australians aged 12 or over eat sufficient serves of vegetables. Nutritionists said changing the balance to eating more plant-based foods and less meat provided a much healthier diet.

Those who have already taken the Meat Free Monday pledge include the cook Maggie Beer, the former tennis champion Pat Cash, the TV chef Simon Bryant and Sir Richard.

"I love eating meat, but I love our planet even more, so I will join this campaign and stop eating meat at least one day a week," Sir Richard said.

A study published in The Lancet recommended that meat consumption should be limited to 90 grams per day. The National Nutrition Survey indicated that many Australians were consuming almost double that amount: on average, men ate 200 grams a day and woman 116 grams.

Dr Stanton said reducing the amount of meat consumed could greatly improve a person's well-being.

"There are strong health benefits to participating in Meat Free Mondays. Eating more plant food is good for us and health authorities around the world recommend against eating high levels of meat," she said.

"Dietary guidelines also recommend much smaller portions of meat than you'd find at a typical Aussie barbecue.

"By going meat free on Mondays, people can help to reduce their risk of chronic preventable conditions such as colorectal cancer and cardiovascular disease."

The campaign was launched by the environmentalist Jon Dee's Do Something! movement and the Fry's Family Foundation.

Mr Dee said the environmental benefits of eating less meat were clear, with the water needs of livestock far higher than those of vegetables or grains.

"People are not aware that producing one kilogram of beef can take thousands of litres of water," he said.

"By reducing our meat consumption we can reduce our environmental impact. According to the Department of Climate Change and Energy Efficiency, our livestock industries are responsible for around 10 per cent of Australia’s total greenhouse emissions."

The campaign runs in more than 20 countries, including the US, Britain, Canada, Japan, Brazil, France and Spain.

Meat Free Mondays Australia has been launched by the not-for-profit Do Something! charity and the newly launched Fry's Family Foundation (the Fry's family runs the Meat Free Mondays campaign in South Africa).

The University of Technology Sydney’s Institute for Sustainable Futures is providing research support for the campaign.