I've been on P90X, lost 5lbs so far on my week 2, and eating a diet that consists of (50% Protein, 30% Carbs, 20% Fats). Besides that I jog during the weekends. I always follow this saying, "Rome wasn't built in one day. So isn't your body. Stay committed. You shall succeed". Best of luck to you and I would recommend like Admiral said 8-10 reps for size and 12-15 reps for lean muscles. Start at 15lb-20lb, don't overload yourself.