Mark, aka The Beast, said he turned down an offer from the ITV series because he didn't feel as though he could cope with the strict diet restrictions.
He explained: “I’ve been asked to do the jungle but the base calorie intake is about 700 calories. Look at me!
“If I survived a week in there I’d probably drop three stone and cannibalism would maybe on the cards.”
However Mark isn't one to say no to all reality TV and last year took part in ITV's first series of Sugar Free Farm.
It sees celebs put on a sugar free diet while working on a farm and The Beast said it had instant results.
He said: “On Sugar Free Farm, the weight just fell off me because I couldn’t eat enough.”
However Mark joked that losing weight may not be good for his career.
He told The Sun newspaper: “Does The Chase need me big? Put it this way, whenever I start losing weight because I’m doing a fitness kick or whatever, the producers go past me and hand me a second portion of pudding.”
Meanwhile, speaking to the Daily Mirror, Mark spoke about his hopes of one day challenging Stephen Fry to The Chase.
“I’d love to have Stephen Fry on the show, I know he’s a genius, but so am I," the quiz show legend declared.