I will have to disagree...
There are three columns to ANY balanced weight-loss program:
Diet
Weight Training (you read that right)
Cardio
In order for you to maximize your results, you need to use all 3 parts, combined, since doing them together apply the principle of sinergy.
Dieting alone will most likely drop your BMR, as the body will adjust to amount of calories you are eating. Weight Training alone is ANAEROBIC (it burns sugar, not fat) and cardio alone has a CATABOLIC effect... This is just oversimplyfing the truth.
To quote Venuto: "Burn the Fat (with cardio) , do not try to starve it with diets."
simply said, get your diet in order, don't cut too many cals, weight train, 3 to 5 days per week and do your cardio. This is a lifestyle change, not a crash course into yoyo efect.
Peace