If you only want to see a change on the scale, then do cardio. If you want to see a change in your body composition, then do strength and cardio. Doing strength training helps you keep your current muscle mass while losing weight. It can also help you give you a leaner look but the weight on the scale may drop more slowly as you won't be losing muscle weight and your muscles tend to retain water after your workouts.
You can't out-exercise poor eating habits.