All Most of these TV "Reality" shows are BS. When my wife and I were diving in Palau we had lunch on the Island that the show Survivor filmed on. Just out of camera view is a picnic grounds with restrooms and a water system (cistern catch basin). The fish are so plentiful in waste deep water you could never go hungry.
I say most because Alone might be the real deal? Yes they have a SAT phone but that actually makes it harder to stay.