First things first: lifting heavier weights will not turn you into the Incredible Hulk. In fact, lifting a heavier set of dumbbells can actually lead to a smaller, stronger you. Sound like just what you're after? Here are two important reasons to ditch the two-pounders and grab heavier weights.
Of course, if you're not used to a weight-training routine, start small and work your way up to heavier weights; starting too heavy can lead to injuries that can sideline all your weight-loss efforts. Here's a chart of common dumbbell sizes for beginners to help you get started; in general, aim for a weight that will fatigue your muscles in eight to 12 reps.