泰国国旗居中蓝色代表（） A.人民 B.和平 C.王室 D.佛教

Dr. Ancel Keys performed an epidemiological analysis of diets around the world (epidemiology being the branch of public health that studies patterns of diseases and their potential causes among populations).

Entitled the Seven Countries Study, it is considered as one of the greatest studies of its kind ever performed. In it, Keys gathered data on heart disease and its potential causes from nearly 13,000 men in Greece, Italy, Croatia, Serbia, Japan, Finland, the Netherlands, and the United States.

it concluded that the Mediterranean people in the study enjoyed some significant health advantages. The Mediterranean groups had lower mortality rates in all age brackets and from all causes, particularly from heart disease. The study also showed that the Mediterranean diet is as high or higher in fat than other diets, obtaining up to 40 percent of all its calories from fat. It has, however, different patterns of fat intake. Mediterranean cooking uses smaller amounts of saturated fat and higher amounts of unsaturated fat, mostly in the form of olive oil. Saturated fats are fats that are found principally in meat and dairy products, although avocados, some nuts, and some vegetable oils also contain them. Saturated fats are used by the body to make cholesterol, and high levels of cholesterol have since been directly related to heart disease.
Several other studies have validated Keys’ findings regarding the good health to people in Mediterranean countries. The World Health Organization (WHO) showed in a 1990 analysis that four major Mediterranean countries (Spain, Greece, France, and Italy) have longer life expectancies and lower rates of heart disease and cancer than other European countries and America. The data are significant because the same Mediterraneans frequently smoke and don’t have regular exercise programs like many Americans, which means that other variables may be responsible. Scientists have also ruled out genetic differences, because Mediterraneans who move to other countries tend to lose their health advantages. These findings suggest that diet and lifestyle are major factors.
The Mediterranean diet gained even more notice when Dr. Walter Willett, head of the nutrition department at Harvard University, began to recommend it. Although low-fat diets were recommended for sufferers of heart disease, group of Mediterraneans in his studies had very high intakes of fat, mainly from olive oil. Willett and others proposed that the risk of heart disease can be reduced by increasing one type of dietary fat--monounsaturated fat--the type found in olive oil. Willett’s proposal went against conventional nutritional recommendations to reduce all fat in the diet. It has been shown that unsaturated fats raise the level of HDL cholesterol, which is sometimes called "good cholesterol" because of its protective effect against heart disease. Willett has also performed studies correlating the intake of meat with heart disease and cancer.