Not eat a lot of food but a lot of bowel movement may be a normal physiological phenomenon, may also be caused by gastrointestinal dysfunction. 1. Physiological phenomenon: If the situation of eating less but having a lot of bowel movements only occurs occasionally, it may be a normal physiological phenomenon. This is mainly due to the large capacity of the stomach and intestines, many times eating metabolic waste are accumulated together, and then a large number of feces discharged at a time. 2. Gastrointestinal dysfunction: Gastrointestinal dysfunction can make patients feel full after eating, so they eat less. Due to the abnormal digestive function of the stomach and intestines, food is stored in the stomach for a long time, causing discomfort, accompanied by the phenomenon of diarrhea, showing the phenomenon of eating less and defecating more. If the phenomenon of not eating a lot of food but defecation, patients should pay attention to, should go to the hospital as soon as possible for examination, and follow the doctor’s instructions to treatment.