But, over the years, the definition of the diet has altered as eating habits have changed, and, anyway, there are 15 countries bordering the Mediterranean, each with a slightly different diet to the next. Researchers have even been testing an Indo-Mediterranean diet of late.

So what actually is the real Mediterranean diet? It was originally defined in the 1950s by researchers who studied the diet on the Greek island of Crete. The islanders seemed to live a longer life than most, and suffered very low rates of heart disease and cancer, despite having a diet that was high in fat.

The fat content of the diet was a problem for the researchers, and so they studied the whole diet, thinking that it must act synergistically. They discovered that, every day, the Cretans would eat cheese, nuts and yogurt, but also fruits, beans, legumes, vegetables, and grain, in the form of bread, or pasta, rice, couscous or polenta, and potatoes. On a weekly basis, the islanders ate sweets, eggs, poultry, and fish and, just once a month, some meat. They also led very active physical lives; very few Cretans were office workers, it seems. They also drank wine, but in moderation.

This became a recipe for healthy living, and was tested on 605 heart-attack patients, who adopted a 'Mediterranean-style' diet. Butter and cream was replaced with margarine to mimic the omega-3 content of the traditional Cretan diet. The rate of further attacks was reduced by 73 per cent - and so a new, healthful diet was born.

(Source: New England Journal of Medicine, 2003; 348: 2599-608).