There are several common reasons for not wanting to eat all day and having a poor appetite: 1. Emotional reasons. When a person is anxious, angry, or emotionally stressed, it can lead to poor eating and no appetite.2. Diseases of the digestive system. For example, when cholecystitis and gallbladder stones, it will lead to not being able to eat greasy food. Various lesions of the stomach can lead to the weakening of the function of the stomach, causing symptoms of no appetite.3, malignant tumors. Malignant tumors can also cause poor appetite and may be accompanied by changes in the sense of taste.4. Hypothyroidism can lead to weakened metabolism in the whole body, which can also cause symptoms of poor appetite. Therefore, it is better to go to the hospital for relevant examination after finding the symptoms.