Muscle vs. Fat

Women don't have enough testosterone to "bulk up." The reason many women think they bulk up when they start lifting weights is because they are putting muscle on (which is awesome - 5lbs of lean muscle mass can increase your metabolism up to 200 calories a day!) but then they are not getting rid of the fat. Muscle does not turn into fat, and fat does not turn into muscle. They are 2 completely separate entities. You want to burn fat and build muscle. Build muscle by lifting weights, and burn fat through cardio. I like to say you can do a million sit ups a day and get a six pack, but it will remain hidden under the layer of fat. So muscle is good, don't be afraid to lift weights, just make sure you are doing your cardio as well.