The correlation of the diet of the inhabitants of Crete with health became widely known through the study of "Seven Countries". This study began shortly before 1960 by the American Ancel Keys and his colleagues, on the occasion impressively low rates of mortality and cardiovascular disease were observed in the area. Indeed, according to the United Nations no other region of the Mediterranean has had such low levels of mortality as Crete, both before and after, the Second World War. The study involved a total of about 13,000 men, who were selected from 16 different locations in seven countries (Finland, the Netherlands, Japan, United States, Italy, Yugoslavia and Greece) in order to investigate the hitherto obscure relationship between diet and cardiovascular disease.The comparisons between different populations showed that the population of Crete had better health and lower mortality rates from coronary heart disease and cancer, compared with all other populations studied. After 20 years of monitoring the Cretans had the lowest mortality rate from all causes, and after 25 years of monitoring deaths from coronary heart disease in Crete was less impressive compared with deaths observed in populations of the United States and Northern Europe but even compared with deaths observed in other parts of southern Europe, such as Italy, Yugoslavia and CorfuThe excellent health and longevity is attributed to the Cretan traditional diet. The food was simple and wholesome oil gave about a third of daily energy in each person, while most of the energy was derived from cereals, especially bread, legumes, vegetables, fruits and occasionally small amounts of eggs, cheese, milk, meat, fish and a little red wine with every meal.

The term "Mediterranean diet", the way it is used today, essentially introduced by food scientists to describe the Cretan diet and the diets of other Mediterranean regions which share features with it, during the decades of 1950 and 1960, when they were no longer overcome the consequences of the Second World War, but before the arrival of fast food culture. Since oil was the main source of fat in the diet of Crete, the term "Mediterranean diet" essentially describes the dietary pattern that prevailed in the Mediterranean where traditionally cultivated olive trees.