Bear Grylls is a jackass.
If you're lost, miles from nowhere, why would you do anything like that bonehead?
He runs everywhere, burning calories and risking a twisted ankle or worse. He climbs everything on sight from trees to cliffs risking further injury.
He gets wet in every episode, crossing stream and rivers needlessly.
He captures venomous or dangerous animals for food, risking injury or illness.
Everything done on that show and others is for ratings. (Not many people would tune in if the dude just sat on one place, conserved energy and water, made shelter, and calmly waited for rescue...)
There's a reason SERE school doesn't emulate anything that clownass does.