P90x will work, but the key is diet. CrossFit will work too, but again the key is diet. P90x provides that meal planning. Stick to that and workout and it will work. Or go slow carb and hit up CrossFit. But the key thing to remember is that you can't out train a bad diet. Garbage in == garbage out.
Maybe you're talking about losing body fat. I'm not sure why you're preaching about that, though, since the parent/GP didn't mention weight loss being a goal.
I enjoy P90x because I do it in my small home office. Its perfect for the non gym goer in my opinion. The results are good. I just do the slow carb diet with it. I hate looking at a 'diet plan'. I lost over 50lbs this year. Right at 15%bf now. Good stuff.
