Muscle is much denser than fat, so it's quite possible for you to experience an increase in body weight at the same time as you lose inches from your frame. If you include strength training into your workout routine, this is a definite possibility. It's for this reason that tracking your weight-loss progress is better done by measuring inches rather than pounds.
Although a pound of fat weighs the same as a pound of muscle, the space these two bodily tissues take up in the body are much different. Muscle weighs much more than its equivalent volume of fat, so muscle takes up less space in the body than fat that weighs the same. This has a significant impact on your body size and body composition.
As you gain more and more muscle, you'll likely notice a difference on the scale. This difference, however, doesn't reflect what's actually happening to your body. Because muscle takes up less space than fat, the increase in weight can lead to a decrease in inches. This decrease in inches has a lot to do with the effect muscle has on your metabolism.
The increase in muscle also has the added bonus of boosting the metabolism. Muscle burns more calories at any given time than fat, so with the increased muscle the body is essentially expending more energy. The increase in energy expenditure can help lead to a caloric deficit, which is needed to shed fat. It takes a deficit of 3,500 calories to lose 1 lb. of fat. More lean muscle makes it much easier for the body to reach this shortfall.
The National Institutes of Health recommends getting at least two days of strength training activities each week. Training sessions only need to last 20 to 30 minutes. In fact, you may start to see a difference in your body composition in as little a few weeks after starting this type of exercise program. Strength training can include your standard weightlifting exercises as well as using resistance bands or your own body weight. Anything that causes the muscles to works on force can increase their mass, tone and strength.