 You can lose weight and actually become fatter as a percentage of your body weight If you were a 200 pound male and you were 10% body fat That means that you have 20 pounds of body fat on your body But let's say you lost 20 pounds of muscle, but you lost no body fat You still have 20 pounds of body fat on your body, but now you weigh 180 pounds Your body fat percentage is now higher because 20 pounds is a higher percentage of 180 pounds And it is of 200 pounds and you'll look fatter in extreme cases Obviously 20 pounds of body fat any 100 pound individual would look very different than on a 200 pound individual