Oysters belong to the mollusk family, along with clams, mussels and scallops. These shellfish are commonly served raw as appetizers, smoked and canned, or breaded and deep-fried.In all these preparations, oysters offer several important nutrients the body needs. Choosing the right variety will help you reap the mollusk's benefits without a lot of added fat and calories.hese shellfish are commonly served raw as appetizers, smoked and canned, or breaded and deep-fried. In all these preparations, oysters offer several important nutrients the body needs. Choosing the right variety will help you reap the mollusk's benefits without a lot of added fat and calories.