Yeah, when you do it right it basically is normal eating. There are a lot of myths surrounding intermittent fasting, and one is that you don't eat as much so it will make you weaker. The problem isn't intermittent fasting, it's people who try it and stop meeting their caloric needs because they think that it means eating less. In actuality, the goal is to eat the same amount, just narrow the window in which you can eat.
Giving yourself 8 hours to eat a day is fairly easy/normal, and in the 16 hours your not eating, your body actually produces more HGH than it would otherwise. I practice it and I have a small to medium sized meal every two hours and hit around 2,500 calories every day. I'm not physically weaker, and haven't lost any muscle mass, but my digestion is definitely better and I've lost a significant amount of body fat.
As far as I know, GSP is doing it to help with colitis, but has experienced several of the the other benefits. There are only cons if you're not doing it correctly, which is easy for people who are getting into fad diets.