Timothy Caulfield, the author of The Cure for Everything, maintains that the multimillion dollar fitness-and-diet industry is sending out the wrong message by telling people exercise will make us slim and give us six-packs.

"You're not going to get sexy abs from doing sit-ups; you're not," Caulfield says, noting instead it's "genetics, and partying hard, probably, and low body fat."

But it's mostly diet. "Fifty percent of what goes in your mouth should be fruit and veg," he says.

For more food and fitness tips, check out Xtra's interview with Caulfield.