Malignant tumor is a kind of consuming disease and nutrition is an important part of tumor treatment. A scientific and reasonable diet can improve the nutritional status of patients, prevent malnutrition and tumor malignancy, enhance the physical fitness of patients and improve the quality of survival, but in actual life, many tumor patients have fallen into the following common dietary misunderstandings. In the traditional concept of some people, making soup is a kind of “great tonic”. Family members make soup for patients, such as black chicken soup, oxtail soup, fish soup, sea cucumber soup, pig’s feet soup, etc., and tell patients that “the essence is dissolved in the soup, just drink the soup and throw away the soup dregs”. In reality, this is wrong. There are very few nutrients inside the soup, fish and meat ingredients, the soup contains non-protein nitrogen, purine, creatinine, a small amount of free amino acids, a small amount of potassium, sodium, calcium, magnesium plasma, low nutrient density, so the soup is not a good source of nutrients for the human body; a large amount of soup will affect the intake of other foods, the diet is single, but will lead to malnutrition. If tumor patients with swallowing difficulty, chewing difficulty, fever, bed-ridden, etc. need to eat liquid food, they can prepare various ingredients, such as grain, eggs, milk, meat, fish, soybean products, vegetables, etc., separately soft and rotten, alone or mixed with homogenizer (soybean milk machine) to make paste and boil into porridge, which is easy to swallow and good for digestion and absorption. The more nutritious you eat, the faster your tumor will grow. Some malnourished tumor patients are mainly vegetarian and believe that “you can’t eat too nutritious food if you have a tumor, otherwise your tumor will grow faster”, even some doctors sometimes ask patients to restrict their diet. In fact, the growth rate of tumor cells has nothing to do with how much nutrition the patient eats. Tumor cells are robbing the nutrients from normal cells until the person dies. Even if the patient is malnourished, the cancer cells will still grow, and starvation will only make the patient’s body consume faster and accelerate the deterioration of the disease. Meat, fish, eggs, dairy and soy products are the main sources of high quality protein, which is an important raw material for tissue cell repair. According to the results of the American Cancer Society study, cancer patients should increase their dietary calories by at least 20% compared to normal; there is no evidence that increased nutrition in the human body will make cancer cells grow faster, but many patients have survived for a long time due to good nutritional status and no malignant fluid. Patients with good nutritional status have a significantly better treatment tolerance and prognosis than patients with poor nutritional status and wasting. There is no scientific basis for the claim that cancer cells can be “starved to death”. The so-called “hairy substances” is an ancient Chinese folk saying, which refers to foods that can cause recurrence of old diseases or aggravation of new ones. Although many patients want to eat them, they are worried about the recurrence of tumor, so they stay away from them. The scientific nature of the relationship between “hairy food” and tumor is yet to be proven. However, there is not enough evidence whether it can cause tumor recurrence. At least so far, we have not seen any cases of tumor recurrence due to the consumption of hair products, therefore, this information is not based on science. 4. Blind reliance on anti-cancer food and health care products Many tumor patients exchange dietary experience with each other during treatment and blindly follow others’ practice, such as blindly supplementing the so-called anti-cancer food and anti-cancer health care products with expensive price. Are these reliable? Certain nutrients or phytochemicals have anti-cancer effects, also in the natural foods they contain are at work. Supplementary nutrients and certain phytochemical preparations as anti-cancer foods and health supplements have no evidence to prove their anti-cancer effects. In fact, this kind of supplementation is not good for the stability and recovery of the disease itself. Tumor is a process of cell proliferation and apoptosis, so it is wrong to ignore the normal diet and spend high price to eat the so-called anti-cancer food. 5. Cancer patients should not eat “spicy” and other foods Avoiding “spicy” and other stimulating foods seems to be a dietary requirement for any disease patients. In fact, this is not based on any evidence: eating spicy food has become a habit in many places in China, but the incidence rate and mortality rate of tumors are not higher than those of other regions; there is no basis that eating spicy food will stimulate the growth of tumors. Many patients only have appetite for spicy food, but after they get tumor, they are asked to avoid eating spicy food completely because of such misunderstanding. In this way, the tumor itself and radiotherapy will cause loss of appetite, and then changing the eating habits of spicy food will often make the patients have no appetite even more, which will not do any good to the patients’ recovery. Heavy taste will increase the appetite of patients and stimulate the secretion of digestive juices, which will help the amount of food intake, and it is meaningless to be too light. 6.It doesn’t matter if you don’t eat as long as you can take nutrition injection. When tumor patients lose appetite and have insufficient food intake, some patients, family members and even individual doctors think that intravenous nutrition can meet nutritional needs without eating. This is wrong. It is the natural state for human body to eat through gastrointestinal tract, and food is absorbed into intestine. If long time does not eat, intestinal mucosa will be atrophied, causing intestinal flora dysbiosis and destruction of intestinal mucosal barrier, thus also easy to be infected. Numerous studies have confirmed that enteral nutritional support therapy can be given for eating disorders caused by various reasons to establish an effective nutritional support treatment channel, and it is used as long as the intestine is functional.