As some have already said before, it depends on the person and their goals. Unlike what some contest prep coaches do, you can't cookie cutter diets for people. It has to be individualized. Myself, a low carb diet (specifically the ketogenic diet) has worked very well in reducing overall body fat. Performance stayed the same (amount of weight moved decreased but had more energy - was on a cut) but I also had a big improvement in overall quality of sleep. In short, I don't think it's a fad at all but good topic!