As doctors said, prevention is number one factor for good health.
Speaking as simple as we can and without the use of special medical terms we must point out the following:

1.Many diseases are caused by the incontrollable receipt of food, especially food containing in excess saturated fatty acids (animal fats), leading to arteriosclerosis and cardiovascular diseases.
Medical studies indicate that Mediterranean countries and specifically Greece, where olive oil consumption is high, suffer less cardiovascular problems from any other country in the world where the ratio of the consumption of animal fat is high or simply the nutrition parameters are poor.
By reducing the animal fats and increasing olive oil in our diet we obtain a perfect combination for the prevention of such fatal diseases, like arteriosclerosis and heart attacks.

2.The problems in bile area torture millions of people on our planet. The bad function of the bile and the formation of gallstone are problems difficult to cure and most of the times medical surgery is the only solution available.
Recent medical studies proved that olive oil, perfectly compatible with human body needs, creates a natural tie to those liquids that result in the formation of the gallstone mitigating pain and annoyance in bile's area.

3.Millions of people around the world suffer by stomach problems and related diseases. Very serious is the gastric ulcer disease. As it is known the use of olive oil in nutrition is a beneficial factor for the function of the digestive system due to its property of keeping low the percentage of HCl in our stomach. Thus, the olive oil helps the normal function of the digestive system reducing to minimum the chances of ulcer creation and the other relative diseases, not to mention that is the best natural medicament for the fight against constipation.                           (source: mediteraniandiet.gr)