Adam Kay, 41, trained as a doctor and worked for the NHS for six years before quitting to become a writer and comedian. Both his memoirs, This Is Going to Hurt: Secret Diaries of a Junior Doctor and Twas the Nightshift Before Christmas, were bestsellers, with several million copies sold, making him the first author to have simultaneous No 1s for hardback and paperback nonfiction titles. He turned both books into hugely successful standup shows. Twas the Nightshift Before Christmas is touring the UK and a BBC Two series of This Is Going to Hurt, adapted by Kay and starring Ben Whishaw, is coming in 2022. He has also started writing children’s books, publishing Kay’s Anatomy last year and, in September, Kay’s Marvellous Medicine. What made you want to write children’s books? I have always been fascinated by the human body; I think it is the most extraordinary bit of kit ever. But it’s never had the same cool billing among kids as outer space and dinosaurs, probably because they’re forced to do biology in a rather dry way at school. So I thought I’d have a go at getting across my enthusiasm for the topic, with some jokes thrown in. Do jokes help children to learn? They absolutely do. It’s a confidence trick. They think they are getting a book full of any number of disgusting facts and jokes but hopefully in there is also an enormous amount of useful stuff about human anatomy and the way bodies and medicine work. Can puzzles and quizzes play a role in learning too? I think gamification is crucial to learning. Whatever age you are, game-playing and adding in a bit of competition to life are great ways of getting yourself to face a challenge. My Fitbit has turned exercise, which I hate, into a game. It nags me to get on the treadmill and to do my 10,000 steps and I do it because I want to win. Did you like playing puzzles and quizzes when you were growing up? We were very much a board-game family. My favourite was called the Game of Knowledge, a kind of knock-off version of Trivial Pursuit, where you travelled round the galaxy answering questions and picking up planets instead of triangles. Cluedo was a big one for us, although I was rubbish at it, and Scrabble, which I was also pretty bad at. What about now? I still play a lot of Scrabble but now mainly on the app, so I am able to lose to Scrabble-playing friends all over the world while distracting myself from work. I limit the number of games I have on my phone because having too many could throw an entire book out. I like playing games with friends in real life, too. There’s a brilliant trivia game called Linkee, which is a big favourite round here when people come over. You’re currently touring with your one-man show, Twas the Nightshift Before Christmas. How’s that going? It’s a 25-show tour ending up at the Hammersmith Apollo on 22 December. It’s lovely to be on a stage again and I think people are just glad to be out. The show is, once again, a confidence trick. It’s billed as funny, disgusting stories from working in the NHS at Christmas time, and it is that, but it is also a big love letter to the million-and-a-half people who give up their festive period to keep the rest of us on the road, particularly after these past couple of years.