A diet has been developed that promises to save lives, feed 10 billion people and all without causing catastrophic damage to the planet.
Researchers have been trying to figure out how to feed millions of people over the decades.
Their response – "the planetary health diet" – does not completely prohibit meat and milk products.
But it is recommended that we get most of our protein from nuts and legumes (such as beans and lentils) instead.
Their diet requires a huge shift in what we lean on our plates and for us to turn to foods that we hardly eat.
What changes should I make?
If you eat meat every day then it's the first biggie. For red meat you look at a burger a week or a large steak a month, and that's your mass.
You can still have a few portions of fish and the same with chicken a week, but plants are where the rest of your protein will have to come from. The researchers recommend instead of nuts and a good help of legumes every day.
There is also a huge boost on all fruits and vegetables that must constitute half of each dish of food we eat.
Although there is a meat on "starchy vegetables" like the humble potato or cassava that is widely eaten in Africa.
So what is the diet in detail?
If you served it all, this is what you would be allowed every day:  – 50g a day
The diet has room for 31g sugar and approx. 50g oils as olive oil.
Will it taste terrible?
Prof Walter Willet, one of the researchers based at Harvard, said no, and after childhood on a farm he ate three servings of red meat a day, now almost in line with the planetary hygiene diet.
"There is huge variation there," he said. "You can take these foods and put them together in thousands of ways. We're not talking about a weak diet here, it's healthy to eat that is flexible and comfortable."
]   Caption: These are some plates of food that meet the planet diet rulesIs this for real, this, or just a fantasy ?
This plan requires changes in dietary habits in virtually every corner of the world.
Europe and North America must cut massively on red meat, East Asia must cut down on fish, Africa on starchy vegetables.  "Humanity has never tried to change the food system on this scale and this speed," says Line Gordon, director of the Stockholm Resilience Center, at Stockholm University.
"Whether it's fantasy or not, then imagination shouldn't be bad … it's time to dream of a good world," she says.
Taxes on red meat are one of the many possibilities the researchers say may be necessary to persuade us to change diet.
Who came up with this?
A group of 37 scientists from around the world were gathered as part of the EAT Lancet Commission.
They are a mixture of experts from agriculture to climate change for nutrition. They took two years to make their findings published in the Lancet.
Why do we need a diet of 10 billion people?
The world's population reached 7 billion in 2011 and is now around 7.7 billion. That figure is expected to reach 10 billion by 2050 and will continue to climb.
Will it save lives?
The researchers say the diet will prevent about 11 million people from dying every year.
This figure is basically down to cutting diseases related to unhealthy diets such as heart attacks, strokes and certain cancers. These are now the biggest killings in developed countries.
Then will this diet save the planet?
The aim of the researchers was to feed more people while:
- minimizing greenhouse gas emissions
- to prevent species from extinction
- having no agricultural land extension and preserving water
. But only changing diets are not close enough.
To get the numbers up, it also requires a halving of food waste and an increase in the amount of food produced on the current agricultural land.
Why is meat not banned?
"If we just minimize greenhouse gases, we would say that everyone is vegan," said Prof. Willet.
However, it was unclear whether a vegan diet was the healthiest solution, he said.
So what's happening now?
The EAT-Lancet Commission will take its results to governments around the world and bodies such as the WHO to see if it can begin to change the way we eat.