And in series two, they introduced coconuts, black pigs, and iguana — as well as lining a muddy pool of water.
The islanders speak to its producers via radio every day, and they also have access to a satellite phone in case of an emergency.
A paramedic can always reach the island within 15 minutes.
And participants are allowed to speak to a psychologist at any point during their stay.
Producers and islanders exchange camera memory cards using a drop box.
And islanders are encouraged to leave foods they are unsure about eating in the box for expert analysis.
Two out of 13 of the first series' participants had previously worked with Grylls.
The island made some participants lose their fingernails.
Producers are told to intervene if participants ask to leave, hurt themselves badly, or become worryingly close to dying.
In series one, producers almost called off the whole show mid-way through filming.
Former islanders say that surviving the experience has made them more confident.
Even though they lost a lot of weight.
Others say that it had a positive influence on their work lives.
And many participants said their relationship with food changed.
Some of the participants received death threats after taking part in the show.
But they also say that the bonds they formed with each other were truly meaningful.