Richard Morris and Carl Franklin discuss the theory of CICO (Calories In vs. Calories Out), a very popular theory about how to lose weight: If you simply create a caloric deficit by expending more calories via exercise than you eat you will lose weight. Does it work? If not, why? Does your body utilize every calorie that you eat? Are all calories burned at the same rate all the time? Does exercise increase or decrease your metabolic rate (calories out)? These are the questions that the dudes tackle on this very technical and even more amazing episode. Errata: An alert listener, Matthew Whited, pointed out that it's gas, not fat, that makes stools float. Reference: http://www.nejm.org/doi/full/10.1056/NEJM197205042861804