This will give you an idea...

The person on the 2 photos has pretty much the same body weight, but on the right photo he has lost almost 15% body fat. This means his weight hasn't changed much but his body composition a lot!



Another example:



As you can see, the 5 lbs. of fat is much bulkier than the 5 lbs. of muscle.

Fat is bulky and lumpy so if you carry an extra five pounds of fat, you'll be lumpier than with five pounds more muscle. A five pound pile of fat will take up more space (volume) than a five pound pile of muscle.

A woman weighing 150 pounds with 19% fat will look much smaller (and be much healthier) than a woman at 150 pounds with 35% fat. They weigh the same, yet the composition is different. Because muscle is more dense than fat the person with less fat and more muscle will look smaller.

It is much more important to pay attention to body composition, rather than on body weight. How much body fat do you have compared to muscle? Simply seeing how much you weigh isn't very helpful.