from theaustralian.com.au: Fast food diets make people fat not just through excess calories but by killing off the gut bacteria that help people burn off their excess energy, a leading British researcher has found. Diets with just a few highly processed ingredients, rather than the dozens of foods found in a healthy diet, are so toxic to these bacteria that it takes only a few meals to wipe out hundreds of the species humans need to maintain healthy digestion, according to research by Tim Spector, professor of genetic epidemiology at King’s College London. The findings emerged from a series of studies in which Professor Spector, whose book on the topic, The Diet Myth: Why America’s Obsessions with Weight is Hazardous to Your Health, is published this week, investigated links between gut bacteria and health. He was seeking insights into why some people put on weight while others stay slim on similar diets — and why less than 5 per cent of fat people succeed in long-term weight loss.