There are many reasons for sudden thinness: first, eating less, insufficient nutrition leads to gradual loss of weight. Second, the mental aspect, due to a long period of poor sleep, mental stress, anxiety, work pressure will also lead to sudden thinning. Third, chronic diseases, such as hypertension, diabetes, as well as some heart disease, stomach disease, liver disease will also appear suddenly thinning and other symptoms. Fourth, tumor diseases, such as lung cancer, liver cancer, pancreatic cancer, breast cancer, etc., tumors are digestive diseases, so there is a significant or sudden loss of weight and other symptoms. It is recommended to go to the hospital for systematic examination to understand the condition and do further treatment.