Paperback: Gulp by Mary Roach (Oneworld, £8.99)

Mary Roach is a science writer who looks very closely at normal things — and close up, lots of things look weird or horrifying. Here, she investigates the alimentary canal, starting at the mouth and working her way down. She investigates the science of taste, which is mostly about smell, and discovers that the jaw has an incredibly efficient braking system.

Sugar itself doesn’t rot your teeth — it’s the bacteria that feed on sugar. She writes about burping and how people train for competitive eating contests. They practise distending their stomachs with water and they learn to chew through the gag reflex. The bit you will talk about most is how prisoners hide things up their bottoms.