In 1901, Karl Landsteiner, an Austrian doctor, found that there are four kinds of blood. These four blood types(血型) were named A, B, AB and O. People have one of these four types. Blood type O is the most common around the world. Blood type A is the second most common, and type AB is the least common. If people with type A blood are given type B blood, or people with type B blood are given type A blood, they will probably die.
In 1927, a Japanese doctor, Furukawa Takeji, carried out research and came up with the idea that people with different blood types also had different personalities (性格). He said that people with type A blood are usually calm and serious; people with type B blood are cheerful and outgoing; people with type O blood are generous(慷慨的) and honest; while those with type AB blood are often caring and careful
More recently, a doctor named Dr. Peter D'Adamo in the United States wrote a book that links(关联）blood types and what people eat. For example, his bookEat Right For Your Typesuggests people with type O blood should eat more meat and less bread. A diet for people with type A blood inc ludes more vegetables. His book has been a hint（暗示)with people who want to lose weight. However, Dr. Peter D'Adamo believes that eating food that matches a person's blood type can do more than help them lose weight. He thinks it will make the person healthier in other ways, too.
