Paris (AFP) - Coming to dining tables everywhere by 2050: porridge for breakfast, rice for lunch, a dinner of lentils and vegetables, and a single hamburger every few weeks, as a treat.

Here is a rundown of the daily meal plan that dozens of health and environment experts are urging the world to adopt in order to sustain a global population of 10 billion by mid-century, while reining in climate change and preventing millions of premature deaths each year.

- Meat is (almost) out -

The team behind a landmark food study published Thursday in The Lancet say intake of some foods such as meat and sugar needs to fall by half by 2050 to reduce the global burden posed by the three billion people on Earth who are either over- or under-fed.

While richer nations must drastically slash their meat consumption, regions such as South Asia currently experience a dearth of calories and protein from a lack of red meat.

Livestock farming is catastrophic for the environment, producing up to 18 percent of global greenhouse gases and contributing to deforestation and water shortages.

Under the new regimen, adults would be limited to 14 grammes of red meat a day -- equivalent to half a rasher of bacon -- and get no more than 30 calories from it.

A quarter-pounder burger patty contains roughly 450 calories and North Americans alone consume more than six times the current daily recommended red meat intake of between 50-70 grammes.

The diet recommends no more than 29 grammes of daily poultry -- around one and a half chicken nuggets -- and 13 grammes of eggs, or just 1.5 a week.

- Fruit and veg up -

The team said consumption of fruits, vegetables, and legumes such as chickpeas and lentils must increase more than two fold, particularly in poorer nations where more than 800 million people get insufficient calories.

More wholegrain foods such as barley and brown rice are needed, but starchy vegetables like potatoes and cassava are limited to 50 grammes a day.

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The authors of the report noted that the ideal diet would vary from region to region, stressing that their menu was designed to show how everyone could get their 2,500 daily calories, keep healthy and aid the planet.

"Eating less red meat –- which is mostly a challenge in changing human behaviour –- is crucial," Johan Rockstrom, director of the Potsdam Institute for Climate Change Impact Research and one of the authors, told AFP.

"But something equally dramatic that is less talked about is the reduction in conventional cereal and tubers, and the transition to nuts, fruits, vegetables and beans as a principal source of nutrition."

- Good news for nut lovers -

The authors estimate their diet would improve intakes of most vital nutrients while slashing consumption of unhealthy saturated fats.

Healthy sources of fat such as nuts and seeds receive a boost: You could eat up to 75 grammes a day of peanuts, but would need to cut back on other unsaturated fats such as oily fish on those days.

Ultimately the new diet could globally prevent up to 11.6 million premature deaths per year, according to its creators.