Live on location at the Cambridge Science Centre, Chris Smith is joined by exercise scientist Dan Gordon, who also holds the world record in tandem cycling, epidemiologist Nita Forouhi, who studies diet, and David Ogilvie, who investigates how our environment can shape our activity. Together they pit their wits against the assembled public as they answer questions like, is watching the Exorcist a replacement for exercise? Plus Dave Ansell and Ginny Smith find the iron on breakfast cereals, measure the vitamin C in carrots, and see how much exercise it takes to work off a Mars bar...