There are three general reasons why weight does not change but face increases: First, normal obesity, as people become fat after the increase in subcutaneous fat on the face, it will be seen that the face becomes larger. However, because after obesity, the body fat increases but the muscles and bones do not have big changes, so the weight will not have big changes. Second, the reason why the weight does not change but the face becomes bigger may be puffiness. Many diseases can lead to excessive subcutaneous water swelling phenomenon, when the face is swollen, see the face become bigger, but the body’s bones and muscles do not have a big change. Therefore, there will not be much change in the whole weight. Third, due to some diseases, such as periodontitis and mumps, as well as allergies, can cause the face to become locally larger. Look at the face big, but the whole body weight does not increase.