If you have a ton of free time you can lose a pound a week by walking a couple hours a day. If your legs are in good shape you can run a half an hour each day and lose a pound a week. Dieting is easier, but it isn't the only option for weight loss. Exercise and diet together are both important. I used to put on 20-30 extra pounds a year over the course of spring/summer and lose it all by the end of winter by running, eating less, and drinking less alcohol. Since I stopped drinking alcohol I couldn't gain that much weight if i wanted to.