Spector is professor of genetic epidemiology at King’s College, London, where he specialises in twin studies, genetics and epigenetics, and diet. Readers of his earlier book Identically Different will know that he is also interested in the human microbiome—the innumerable microbes that live on and especially inside us, and this is a central preoccupation in the present book. Spector believes that it is the key to understanding why diets to control our weight nearly always fail in the long run. Continue reading