I have been thinking of a setting that involves a person getting stranded in a temperate forest that has not been previously inhabited. He eventually meets other people but until then he has to survive with what he has.
He has little knowledge on how to forage but, due to a quirk of his situation, he can regularly obtain large amounts of fresh fish. He also has three pieces of potatoes with him along with some knowledge of how to grow them. I'm trying to figure out if this person could survive indefinitely on a diet of only those two things, but I'm wondering if nutritional deficiencies will eventually catch up to him.
Edit: I'm considering having them be willing to eat raw parts of the fish.