There is actually a diet that consists of only fruits and some nuts and seeds.
So I've heard, wasn't Steve Job on that diet?
Not sure about that but these people are usually considered fruitarians.
Do they it for health reasons?
Its basically a subset of dietary veganism.
Do you know why people becomes frutarian instead of vegetarian?
Its usually for ethical, religious or environmental reason. Sometimes even health or cultural
Really?  What religions promote that diet?