The UN body planned to support the launch event of the scientific group behind the controversial 'planetary health diet', dismissed as 'nanny-state' madness.
Scientists say its adoption is vital to feed the world's booming population without destroying the environment and would improve the health of millions.
But the WHO stopped sponsoring the event following criticism there is 'no scientific justification' for everyone in the world to adopt a standard diet.
The British Medical Journal first reported the WHO had dropped out of the EAT-Lancet Commission on Food, Planet, Health event in Switzerland. The event - promoting a diet first announced in a report in January - still went ahead in Geneva at the end of March. It was sponsored by Norway's government.
It is unclear what prompted the body to pull its sponsorship, however, the views of Italy's ambassador to the UN may have played a role. Gian Lorenzo Cornado penned a letter to the WHO which questioned whether the agency should back the global push for countries to encourage the diet. In a scathing attack, he argued that it could cause millions of people working in the agriculture industry to lose their job, as well as other food areas.
Mr Cornado also warned that the global shift to a plant-based diet could spell an end to traditional cuisines across the world. He added, in a letter seen by the BMJ, such a move also risked the 'total elimination of consumers' freedom of choice'. And he said the plant-based regime 'is also nutritionally deficient and therefore dangerous to human health' - despite evidence of the dangers of red meat....read more>>>...