It’s not often a book changes my life in a mere three chapters, but a quarter of the way through The Diet Myth I went out to buy some natural yoghurt for breakfast. A hundred pages or so later, on learning of the benefits of intermittent fasting, I decided to have it for lunch instead.

Given my usual reluctance to jump on any passing nutritional bandwagon, I reckon this makes Tim Spector’s work a rather compelling read – the more so since, unlike many of the current crop of shiny-haired and dewy-skinned ‘nutrition experts’, he is a professor of genetic epidemiology at King’s College London and has over seven hundred academic papers to his name. Even more reassuringly, his arguments here are backed up by twenty-five pages of notes and references.

Spector’s subject is the incredible four pounds of microbes resident in our digestive system, the significance of which is only beginning to be understood by scientists. Somewhat unnervingly, it seems your body contains ten times as