Low fat diets were the conventional wisdom for quite a long period of time. Lots of people got lean and athletic on them and still do. > If calorie in/calorie

Low fat diets were the conventional wisdom for quite a long period of time. Lots of people got lean and athletic on them and still do. > If calorie in/calorie out worked then obesity wouldn't be a problem in the USA because 99% of obese people have been treated that way. There are two ways of looking at whether a diet "works." First, what happens when a person actually follows the diet. This is what most people are curious about. Second, what happens when you tell a person to follow the diet. This is what all the scientific papers are written about because it's what doctors, public health experts, and other researchers care about. Don't get the two mixed up. From the first point of view, there's a wide variety of very different diets that "work." From the second point of view, basically nothing works, and there is a never-ending (re)search in which occasionally somebody announces weak evidence that the diet du jour is better than yesterday's favored diet, but there's no reason to believe the current conventional wisdom will last any longer than previous expert consensuses such as the need to eat low-fat.