Dr Richard Mackenzie is one of the UK's foremost experts on glucose metabolism, insulin resistance and their interactions with stress hormones. Dr Mackenzie is a leading researcher at Research Centre for Health & Life Sciences (Coventry University) and the Institute of Cardio-Metabolic Medicine (University Hospital Coventry and Warwick NHS Trust) and is internationally recognized for his work. He leads on metabolic health at a distinguished Harley Street clinic and has published more than 40 journal articles, mainly on insulin resistance and diabetes.

Peter Walker is senior political correspondent with the Guardian and a well-known commentator and frequent broadcaster on active living and health, as well as on politics. As a journalist he has also worked for Agence France-Presse, CNN and others, reporting from places including China, Iraq and North Korea. He has written two previous books, including The Miracle Pill, which explained how everyday physical movement has disappeared from the modern world, and the health consequences this brings.