Over a century ago, a 'scientific breakthrough' ushered in radical dietary changes that saw the US, and eventually most of the world, put on a low-fat diet. The discovery that high cholesterol levels were associated with coronary heart disease led to saturated fats, particularly animal fats, being singled out for elimination from meals. In theory, they told us, people will get less heart attacks and become healthier. But what actually happened? Rates of coronary heart disease rose to today's...