How can it be that the British ate better, nutritionally speaking, during the rationing years of the Second World War than they have since? And how did we get to the point today where each of us has at least 300 man-made chemicals sloshing around inside our bodies, in untested and potentially toxic combinations? To find out how our food came to make us fat rather than healthy, James Fergusson turns to the scientist who devised the wartime diet and follows a murky trail of industrial espionage, unsolved murder and commercial greed right onto the plates we set before our families every day.