It’s a multi-billion dollar battle for your belly. Millions of people are joining the anti-wheat revolution. Kellogg’s, the world’s largest cereal maker, has seen its biggest drop in sales since the 1970s. Food companies are selling off their struggling bread divisions. It’s all because best-selling health evangelists say that wheat is causing everything from fat bellies to schizophrenia. But do they have science on their side? Mark Kelley takes a hard look at what’s driving a movement that is dramatically changing the way we eat.