The Mediterranean diet. In 2010, UNESCO declared it an Intangible Cultural Heritage and it is the combination of eating habits followed by the coastal populations of the Mediterranean Sea for millennia. It consists of a varied and sensible mix of foods, combined so particularly that it provides all the necessary nutrients for a healthy life. In this final result, the olive tree’s leading role is vital and it is the cornerstone when preparing dishes of the Mediterranean diet. This importance of olive oil is beyond doubt and depends on its many virtues, both gastronomic and for the health. Its nutritional merit is guaranteed by the fact that olive oil is the food that contributes the most calories to our diet, making it the key element that enables the culinary customs of countries as diverse as the Iberian Peninsula or the Near East to come under the heading of Mediterranean diet. It could be said that the Mediterranean diet would not exist without olive oil, since without it, we would not be able to prepare most of the dishes in this diet. Olive oil is a valuable food because of its richness in various components, including oleic acid, the diet’s most important monounsaturated fatty acid. Olive oil is the only natural product in the world that is largely made up of this fatty acid. Thanks to our oil, the menus of our diet are a balanced mix of products, where each one retains its nutritional properties, providing its best sources of calories, proteins, vitamins, minerals and other micro-nutrients. A good example of this is the traditional and healthy custom of eating bread and oil at breakfast time, or the use of olive oil when preparing traditional pastries.