Rich in vegetables, fruits, cereals and extra virgin olive oil, the Mediterranean diet is based on a moderate consumption of fish, eggs, red wine, and a small amount of meat.[Photo provided to China Daily]

It also puts at risk of extinction local skills and traditions such as harvesting, fishing, animal husbandry and conservation.

Healthy eating has not fallen by the wayside completely: the Mediterranean diet is a hit with "educated people and those who belong to higher social classes" in Greece, Trichopoulou said.

"It is more related to a social problem and education than money, because vegetables and fruits are relatively cheap," she said, but people are cooking less and advertisements promote sugary or preserved products.

What's needed is to encourage initiatives in local communities and find a way of selling sustainable tourism－including a return to local food production－even in mass tourism areas, says independent expert Florence Egal.

In Spain's Balearic Islands, including the hugely popular Majorca and Ibiza, "thousands of tourists eat at buffets in large hotels", while "in the countryside orange trees are weighed down with unpicked fruit", which rots because imported oranges cost less.

And she warns, as groves are abandoned and migration to cities increases, the Mediterranean diet takes one more step towards becoming a thing of the past.