Question: Ton Hanks spends 4 years on the island, subsisting on nothing more than rainwater, coconuts, and fish. It's not shown, but possibly he might have caught some birds, too. He lost weight on that diet, but wouldn't the lack of certain vitamins and nutrients given him scurvy, pellagra, beri-beri to the point of death? (Scurvy takes just a few weeks to set in.).