Constipation during weight loss may be caused by physiological factors such as drinking too little water and insufficient fiber intake, or it may be caused by other reasons such as hemorrhoids and irritable bowel syndrome. 1. physiological factors: drinking less water during weight loss or clear, bananas and other fiber-rich food intake is relatively small, may lead to dry stools, defecation difficulties and other constipation performance. 2. Hemorrhoids: hemorrhoids etiology is not yet clear, clear considerations with the anal cushion down, rectal varicose veins and other factors. Patients will have anal pain, bleeding and other manifestations, some patients will be afraid of pain during defecation, and the symptoms of constipation, so hemorrhoids will be constipated during weight loss. 3. Irritable bowel syndrome: the cause of irritable bowel syndrome is not clear, may be related to visceral hypersensitivity, gastrointestinal dynamics abnormalities and other reasons. Patients mainly manifested as abdominal pain, constipation, diarrhea, and so on, so that the patients lose weight during the emergence of irritable bowel syndrome will appear constipation symptoms. If the constipation during weight loss is caused by physiological factors, no treatment is needed, and it usually improves after drinking water and improving diet. For diseases that cause constipation during weight loss, it is necessary to consult a doctor in time and follow the doctor’s advice to choose the appropriate measures for treatment.