According to a report from the Stockholm International Water Institute (SIWI), the world population will have to change to an almost exclusively vegetarian diet by 2050 in order to avoid catastrophic shortages of food.

Malik Falkenmark, SIWI researcher warned that "if we follow the current trends and changes to diets similar to those of Western nations, there will not be enough water in the current agricultural lands to produce food for a global population that is expected to be 9,000 million by 2050."

Currently humans obtain about 20% of the proteins ingested from animal products. However this number may need reducing to 5% in order to feed another 2 billion people, once the global population expected to reach 9 billion by 2050.

"We will need a new recipe to feed the world in the future," said the report's editor, Anders Jägerskog.