I probably shouldn’t be telling this story. It starts in 1968. According to (brilliant) researcher, surgeon and writer Atul Gawande, in that year, The Lancet published findings that represent one of the most important medical advances of the last century. It was just this: David R. Nalin and Richard A. Cash, American researchers in Dhaka during a cholera outbreak, added sugar to salt and water hydration and administered it orally to 29 patients. Cholera deaths: zero. Sugar, it seems, helps the gut absorb fluids. Cholera pandemics killed millions in the nineteenth century. Even after intravenous fluids reduced mortality to 30 per cent in the early years of the twentieth century, globally, most people died, especially in places where...