Sushi is thought to be a Japanese delicacy, but it's actually Chinese in origin. There, sushi-making was a method used for preserving fish by fermenting it in salt and rice. The ginger is considered a palate cleanser. Sushi is low in fat and typical setting of 7 to 9 pieces has about 300 calories. However, a major concern for people is that the raw fish may harbor parasites that can cause sudden gastrointestinal upset or reactions ranging from hives to shock.
Cooking can also kill the parasites.