Weight loss without loss but thin appearance is usually caused by a decrease in the amount of body fat and a relative increase in muscle mass. Many people who work out have this appearance. Physical exercise, you can exercise muscle strength, increase the number of muscle fibers, so that the overall weight of the muscle increased, but the shape is better. However, physical exercise, reduces the content of body fat, fat is relatively fluffy and occupies a larger space, so the performance of the weight has not been reduced, but the appearance of thin. Once you find that you have not lost weight but have lost weight in appearance, you can make a preliminary judgment by recalling whether you have changed your lifestyle recently. If you are not sure, then you can consult your doctor in time.