Ancient Giants: Legends of Anakims and Nephilim

Could we speculate that there were not just individuals like Goliath, but entire races of gigantic people, suggested by some as the Nephilim from the Bible?

Anthropologists believe that they may have identified an ancient subgroup species of giant humans ranging from 7 to 14 feet tall, citing skeletal evidence and centuries old witness accounts on record by explorers and tribal Indians.