There are a number of points I could address, but I'll just say that any diet that leads to weight loss while also keeping you feeling satisfied is going to be way more effective than something that requires you to control your appetite. I'm sure there are others that do this, but Tim's version of Slow Carb is one of them.

Of course, with a whole lot of knowledge and a whole lot of self-control, you could be more effective, but Ferriss's whole idea is being effective with minimal effort.