LONDON, England (CNN) -- Famed for keeping people slim, healthy and living longer, the Mediterranean diet has followers all over the world.
Cultural treat? Moves are underway to get the Mediterranean diet on UNESCO's world heritage list.
However, the diet is being increasingly shunned by people who live in the Med as the convenience of fast food gains popularity.
The renowned low-fat, high-fiber diet has "decayed into a moribund state" in its traditional regions, according to the United Nations Food and Agriculture Organization (FAO).
So sharp is the decline that governments from the region are scrambling to protect their traditional fare from becoming an "endangered" species.
Populations surrounding the Mediterranean Sea, such as Greece, Spain and Italy, tend to eat these foods, and governments there have joined forces to apply for their diet to be placed on the United Nations Educational Scientific and Cultural Organization's (UNESCO) Heritage list.
Those lobbying for UNESCO protection have argued that its inclusion would ''fend off the watered-down clones assailing its integrity worldwide in this age of killer fast food.''
The UNESCO list is famous for including historic and cultural sites but in recent years the UN body has opened its register to include ''intangible heritage," such as endangered languages or vanishing traditions.
"The Mediterranean diet is a heritage that should be protected and shared," Paolo de Castro, a former Italian Agriculture minister, said earlier this year.
"Science has long recognized the unusual health properties of the diet, which has strengthened and accompanied the common cultural identity of Mediterranean countries," he said, according to Italian news agency ANSA.
"The diet is an integral part of the historical and cultural identity of the Mediterranean, and an opportunity for growth for the countries in the area."
Originally considered the diet of the poor, who didn't have much money to buy meat, the "Mediterranean diet" is rich in fruits, vegetables, nuts, cereals, whole grains, fish and olive oil.
Numerous studies have associated it with long life-spans and low rates of cancer, heart disease and other ailments. See a comparison of the old and new diets in Mediterranean countries »
However, some fear that it has become supplanted by supermarket ready-made foods and fast food as people have become more cash-rich and time-poor.
"The European diet has become too fat, too salty and too sweet," senior FAO economist Josef Schmidhuber concluded in the group's report on the European Union diet.
The FAO's 2008 report ranks Spain as the country with the biggest leap in fat consumption in Europe -- from 25 percent of the diet 40 years ago to 40 percent now.
EU and Mediterranean countries with the worst dietary changes are Greece, Italy, Spain, Portugal, Cyprus and Malta, where calorie intake has increased by 30 percent in the last few decades.
Three-quarters of the population of Greece is overweight or obese, while in Spain and Italy the number is more than 50 percent. In the U.S., 66 percent of the population fits into this category.
Alarmed by the growing health problems associated with obesity, Spain's Health Ministry has launched a series of initiatives to combat obesity. In 2007, it ordered fast-food chain Burger King to remove ads for its Big King XXL, which contains 1,000 calories, and which were aimed at teenagers and young people.
A 2001 report by Foodservice Intelligence, a London-based market research firm, found that traditional-style restaurants in Italy and Spain were outnumbered two-to-one by their fast-food counterparts.
UNESCO will decide whether to include the Mediterranean diet in its Heritage list late next year.
Until then, Spain and other countries in the region undoubtedly will hope they can retain their reputation as a rewarding destination for the gourmet traveler.