Yeah it is staged up to a point. they certainly pick personalities that will clash or maybe get along a little to well (if you know what i mean) for the cameras, but the lack of food and getting their own shelter and such is real. Have you ever seen what happens when they win coffee as a reward, its hilarious to see them all buzz. Also the weightloss is definatly not staged, some of them look like skeletons by the end of it.
There was actually a rumour that in the outback season, some smarty found out where they were and flew over and dropped chocolate bars down to them. Don't know if thats true or not, but made me laugh all the same, and when you see people like russell pass out and be near to the point of his heart failing, or the other guy who fell in the fire and had his skin hanging off his hands, you know not all of it is staged. I like the challenges most of all, and seeing how they cope with the elements. like Allan L said if Jimmy Johnston says its one of the toughest things he's ever done, then i'm inclined to believe its pretty darn tough.
cheers guys and happy watching.