This book has been a long time in gestation and many people have helped me along the way to deliver it, whether by a chance comment or a detailed explanation or sending me wacky YouTube clips. Getting the book off the ground is often the hardest part, and my agent and friend Sophie Lambert of Conville & Walsh has been essential and a fantastic support. The book has been through several transformations, each one guided enthusiastically by my highly skilled editor at Weidenfeld & Nicolson, Bea Hemming, who I learnt from and who was a pleasure to work with. Several people deserve special mention. Kirsten Ward helped me research many of the topics and select the case histories, assisted by my intuitive assistant Victoria Vazquez, both of whom diligently read some very early bad drafts. Later versions were read and improved by old and trusted friends Robyn Fitzgerald, Roz Kadir, Bryan Fehilly and Frannie Hochberg.
My colleagues in obesity genetics, nutrition and the microbiome were invaluable sources of the latest information before it was published. These include my microbe collaborators Ruth Ley and Rob Knight, plus his team from American Gut, Dan McDonald and Luke Thompson; Dusko Ehrlich, Peter Turnbaugh, Paul O’Toole, Glen Gibson, Susan Erdman, Stan Hazen, Amir Zarrinpar, Marty Blaser, Maria Dominguez-Bello, Patrice Cani, Kevin Tuohy, Laurel Lagenaur, Rashmi Sinha and Jim Goedert, as well as my King’s College London team, Michelle Beaumont, Jordana Bell, Craig Glastonbury and Matt Jackson. Other brains I quizzed include Steve O’Rahilly, George Davy Smith, Mark McCarthy, David Allison, Clare Llewellyn, Kirsi Pietiläinen, Ele Zeggini, Alina Farmaki, Barbara Prainsack, Aubrey Sheiham, Leora Eisen and David Morgan.
I had very helpful conversations with my KCL colleagues Kevin Whelan, Jeremy Sanderson, Phil Chowienczyk and Tom Sanders. In Barcelona, merci to my generous host Xavier Estivill and Ramón Estruch, Mark Nieuwenhuijsen, Susana Puig and Josep Malvehy for their knowledge and hospitality. I learnt about cheese from Paul Neale, Jon Schofield, Nigel White and Eric Biseaux, and about food philosophy from Julian Baggini. Helpful tips came from Ian Weir, Aine Kelly, Isgar Boss, Amanda Bailey, John Hemming, Swami, Brenda Sambrook, Lesley Bookbinder, Vivienne Hall and others whose names I have forgotten but whose tips were equally helpful. I thank my gifted son Thomas for his junk-food sacrifices and the other diligent and adventurous dieters, and all the TwinsUK volunteers. I must thank St Thomas’ Hospital, King’s College London, my funders at the EU, NIHR and Wellcome Trust and as always the amazing twins for providing me with such a perfect base for research, and Veronique, Sophie and Tom for generously allowing me to disappear from real life for long periods.
Finally, despite all the help I received, this is a vast and fast-moving area of science which means I will surely have made some errors and omissions, for which I happily take any blame.