Plus the stuff I do when I’m on the road – improvising with jerrycans or whatever weights we can find." That improvisational approach to training has informed Grylls’s latest venture.
The BG Survival Academy now runs courses for all ages, including a parent-and-child option that’s booked up for years in advance. "I think people love to challenge themselves," he says.
"They want to feel they have some of these traditional 'man' skills – which really apply whether you’re a girl or a boy, of course – and feel they can look after themselves." And they don’t just do what Grylls calls "the boring bushcrafty stuff" – a lot of it is based on the UK special forces training he knows well. "In the old days we just carried heavy packs over long distances, and now it’s a much more dynamic sort of strength.
"I cooked last night, actually – got back from filming in the mountains for three days and said, 'right, I’m cooking'.
I did a big spaghetti bolognese made out of buffalo mince with buckwheat pasta – non-wheat but it’s great, really healthy, delicious stuff – and then I made a big chocolate mousse with raw cocoa, maple syrup and coconut oil and an egg." Perhaps inevitably, Grylls has a nutrition book due out next summer.
"I wasn’t able to do huge weights but over the months I was getting leaner, stronger and more flexible," says Grylls. I only run occasionally these days but the strange thing is, I’m much better at it than I used to be.
My heart and lungs are so much bigger because we do so much high-intensity stuff. And I still get that 'shaking muscles' feeling a day later – I used to have to train for three hours to get that.
"That means I’m experimenting with a lot of recipes – and the boys love it as well.
I wish at school someone had taught me to eat healthy.
He learned to climb and sail young, got a black belt in shotokan karate as a teenager and went hiking in the Himalayas after leaving school.