For the longest time, the people who spent their careers studyingnutrition could only guess at the extent to which people were attracted to sugar. That all changed in the late 1960s, when some lab rats in upstate New York got hold of Froot Loops, the super-sweet cereal made by Kellogg's. The rats were fed the breakfast cereal by a graduate student named Anthony Sclafani who, at first, was just being nice to the animals in his care. But when Sclafani noticed how fast they gobbled it up, he decided to concoct a test to measure their zeal.