It is normal for people to have small changes in weight after surgery, but it is also normal for patients who have been fasting for a long time to lose weight after surgery, especially when it comes to duodenal, partial small bowel resection or gastric reduction surgery, patients who have short bowel syndrome or solvent reduction after surgery may lose a lot of weight in a short time, at least 70% of their excess body weight. Therefore, for surgeons, long-term nutritional support is needed for such patients, such as intravenous supplementation of carbohydrates, fats, proteins, as well as various trace elements, electrolytes, vitamins, etc., which are needed by the body. If experienced clinicians who have taken various nutritional combinations for a long time, there will be no significant change in the patient’s postoperative weight when treated accordingly.