People that live the longest have the smallest intake of meat, according to an internationally published nutritionist.

Certified dietician and author Jonny Bowden said there were a wide range of diets from the Bantu of South African and the Inuits of Greenland.

The Bantu ate a diet of 80 per cent carbohydrate and the Inuits ate virtually nothing but blubber and seal meat, he said.

Meat intake depended on individual metabolisms, he explained, but factory-farming and hormones in food were warning signs people should take heed of.

"I do think that even the longest lived people the world may eat very little meat, but they eat a little bit of it," Mr Bowden added.

Eating meat as little as once a week could be of benefit, he said, with a diet rich in fish potent in B12 and omega 3s.

According to the World Health Organization, 2.7 million deaths are attributable to low fruit and vegetable intakes.