In contrast to other types of crab, blue crabs contain a significant amount of meat. On average, they have about two ounces of meat per crab. This nutritious meat is an excellent source of protein, calcium, iron, and vitamin B12 and is also low in fat. Likewise, stone crab claw meat is also a good source of protein, with little fat. However, you only get a small amount of calcium and iron in each serving. Therefore, three claws contain only 60 calories and 0% fat.