Loggerheads eat crabs, clams and other shellfish.
As a small hatchling, almost everything. Anything that can fit a small hatchling into its mouth, will do so. Most common predators of eggs and hatchlings on land are racoons, herons, ghost crabs and sea gulls. Most common predators in the water are any large fish and sharks. Once a turtle gets to adult size, several feet in length, then it has very few predators.