No. Coffee/tea here and there along with a healthy diet and consistent exercise regimen. Nootropics don't work in my opinion if you are out of shape and lacking basic nutrients for normal body functions. Don't even get me started on energy drinks.
It is not a scam. I don't do it personally, simply because the workouts they do are not in line with my goals. I have been working out regularly for a few years now. Starting my 11th month of jim wendler 5/3/1. Give crossfit a shot you might like it.
I think if you can find a good affiliate to work out at it can be beneficial because they have some really good coaches that can hammer good form in the Olympic lifts. But if your just starting out there are plenty of beginner programs like Starting Strength. It don't think that it is a fad at all. They do like to push the carb backloading and paleo diet a little much. But if you clean up your diet and eat healthy you can achieve your goals crossfit or no crossfit.