If the fitness industry wasn't a scam, it wouldn't be an industry to start with. C'mon, as everyone here probably, I tried to find out as much as possible about nutrition, training, etc.....How much do yo really need to know to get satisfying results? I had a good coach (who trained professional athletes). Himself agreed that after a 10-hour course, you knew 90% of what you needed to know and the rest was debatable. Same with nutrition. Some supplements might be useful....if you're not eating according to your training. It come in handy if you're lazy (and we all are at one point). As someone said, the only "supplement" that drastically changes the picture are steroids (I'm a natty). So if they were legal, it would be marketed as the only real game-changing supplement and clients would have to make up their mind if they want to go that road or not. As simple as that. Training and "growing" doesn't need much of a financial investment in fact.