“Doctor, does the patient need to avoid eating?” “Can I eat spicy food? Many such questions often bother the patients and make the outpatient doctors headache, so what are the common misconceptions that cancer patients should not have so many worries about their diet and what are the common misconceptions that can help cancer patients? Myth 1: The more nutritious you eat, the faster your tumor will grow? In the clinic, we often encounter very thin patients who are mainly vegetarian and seldom eat meat and eggs, so the patients or their family members will say, “Some friends say that if you have a tumor, you can’t eat too nutritious food, otherwise it will cause the tumor to grow bigger, so we don’t let you eat meat?” But in fact, the growth of tumor cells has nothing to do with how much nutrition a patient eats. Cancer cells are robbing normal cells of nutrients until a person dies, and even if a patient is malnourished, cancer cells still grow. According to the results of the American Cancer Society, cancer patients should increase their dietary calories by at least 20%, and there is no evidence that increasing nutrients in the human body will make cancer cells grow faster, but many patients have survived for a long time because of sufficient nutrients. As a gastroenterology oncologist, we pay most attention to patients’ nutrition in our clinical work. Patients with good nutritional status are significantly better than those with poor nutritional status and wasting in terms of tolerance to treatment and prognosis. The saying that cancer cells can be “starved to death” is not based on science at all. Myth 2: It is inevitable for cancer patients to continue to lose weight during treatment, so don’t worry too much? There are several reasons why cancer patients continue to lose weight during treatment: 1. when receiving radiation and chemotherapy, the weight loss will be caused by side effects such as mouth ulcers, nausea and poor appetite; 2. cancer cells compete with normal cells for nutrients and the body consumes energy to fight against tumors; 3. cancers in the digestive system such as esophagus and stomach affect nutrient absorption. Generally speaking, if the treatment is effective and the tumor is under control, even if there are some side effects, the weight will be recovered quickly after the side effects disappear, especially for digestive system tumors, this performance is especially obvious; if the patient loses weight during the treatment process, the cause must be considered, and the side effects caused by the treatment need to be reduced by some ways If the tumor of digestive tract affects the absorption, the intake of nutrients can be improved by supplementing enteral nutrients on the basis of normal diet. Research shows that 50% of patients have lost weight when cancer is confirmed. Tumor cells affect human metabolism and it is inevitable to lose weight, but providing appropriate nutritional support during treatment can help improve patients’ physical condition and increase survival rate. Myth 3 Meat will encourage cancer cells, so vegetarian diet is better? Many patients or family members believe that “eating fish, chicken, beef, etc. is not good for health”, and these information are usually obtained from the internet, some patients or friends. For example, some post-operative patients believe that fish and chicken are “hairy” and will cause wounds not to heal, so they eat vegetarian food for a long time after surgery, resulting in insufficient calorie and quality protein intake, and insufficient essential components for tissue cell repair, which will cause wounds not to heal, while the continued decline in immunity will also increase the chance of infection. Therefore, we remind patients that “meat will not accelerate the growth of tumor cancer cells”, and vegetarian cancer patients should eat various vegetables and fruits in addition to supplementing whole grains, beans, eggs and milk to have a balanced diet, which can help the organism recover health as soon as possible. Myth 4: Cancer patients should eat as light as possible, and it is better to eat less greasy food? Even a light diet should be supplemented with other essential nutrients. Fats and oils contain essential fatty acids for the human body, and good fats and oils such as olive oil, bitter tea oil and other fats and oils with high unsaturated fatty acids, fish containing omega-3 fatty acids, and nuts should be consumed by cancer patients, which are helpful to enhance immunity. Myth 5: Cancer patients should not eat “spicy” foods Doctors are often asked, “Does cancer mean you can’t eat spicy foods?” But in fact, these answers are often lack of basis. In many places in China, eating spicy food has become a habit, however, the incidence rate and mortality rate of tumor are not higher than other regions. Many patients have appetite only when they eat spicy food, and after they have tumor, they are asked to completely avoid eating because of such misunderstanding, in this way, tumor itself and radiotherapy will cause loss of appetite, and then change the eating habits of spicy food will often make patients have no appetite, which will not do any good to patients’ recovery. Myth 6 As long as you can take nutritional injection, it doesn’t matter if you can’t eat? Many patients will ask the doctor to infuse nutrition after hospitalization, think that intravenous supplementation for a few days, the body will be better, it does not matter if you do not eat, but in fact, the human intestinal nutrition source is mainly absorbed by food into the intestine, if you do not eat for a long time, the intestinal mucosa will atrophy, causing intestinal flora dysbiosis, which is also prone to infection, so as long as you can eat, you must try to intake nutrients through the normal way. Supplementation can be carried out with enteral nutrition preparations. Nutrients such as fatty milk amino acids given intravenously are often difficult for the body to absorb and are more often consumed in the form of energy, even in the form of ordinary drips, which are not as good as a sports drink to replenish energy. Even complete nutrients (carbohydrates, amino acids, fat emulsion, electrolytes, vitamins, trace elements) for medical use can be maintained to improve the nutritional metabolism of critically ill patients who are unable to eat, but they should not be used for a long time. In general, because of the consumption of malignant tumor and the influence of treatment, the nutritional requirements of tumor patients are more detailed than those of healthy people. At present, the Department of Gastroenterology of Peking University Cancer Hospital is conducting a clinical study on the combination of nutritional support and drug treatment for advanced cancer patients, and we hope that the study will give guidance on nutritional interventions for the treatment of cancer patients in the future.