2nd Wind Fitness has an article that covers10 reasons you should lift weights:

1. Lift weights to lose fat: One of the biggest mistakes people make when starting an exercise and nutrition program is not including a weightlifting program with their cardiovascular exercise and low-fat eating regimen. This is unfortunate because when we cut calories without exercise, we can lose muscle as well as fat. And when you lose muscle, your body becomes a lot less efficient at burning fat. However, when you gain muscle, you can actually condition your body to burn fat more efficiently…24 hours a day!