system
Given the following post, respond as if you're commenting on Reddit:
human
[Cast Away] Could our hero have actually survived 4 years on that island?

Is it literally possible for someone with no survival training and no equipment to have survived 4 years on their own?  Especially in terms of nutritional deficiencies.  Never mind simple caloric intake along with shelter and other survival problems.
gpt
I don't see why it wouldn't be. He has fruit, fish, shelter, and fresh water. He's a very resourceful and smart person which is how he is able to learn to survive. 

meta: the movie was heavily researched before being scripted.