If you loose weight, you will be a smaller version of yourself only. I would lift, and lift much heavier then 8 to 12 pounds. You need weight-bearing exercise, it good for your bones and muscle will give you a more defined look. Bodybuilders are supplementing themselves with copious amounts of protein and of course glutamine/creatine and steroids, not to mention hours in the gym lifting. I know there is a lot of arguement that lifting weights will only make you look bigger, but I bet if you lift heavy a couple times of week and follow a good routine that separates out the body, you'll eventually loose weight. Good luck!