Nutritional support is an important part of cancer treatment. Adequate and balanced nutrition is important for tolerating treatment and recovering from treatment. Currently there is a plethora of information about nutrition and therapeutic support for oncology patients, filled with many irresponsible and conflicting views, opinions, and even fallacies, leaving many patients at a loss as to what to do. Nutritional and therapeutic support for tumors is a serious scientific concept, not simply a dietary therapy. This article and several subsequent articles will refer to the most authoritative publication of the American Cancer Society: Complete Guide to Nutrition for Cancer Survivors; Second Edition to concisely describes nutritional support strategies for oncology patients. Unless otherwise noted, the content of this article is derived from these guidelines. Protein provides the body with essential amino acids and is essential for growth, tissue repair, and immune maintenance. Good sources of protein include fish, poultry, lean red meat, eggs, low-fat dairy products, nuts, dried beans, peas and lentils, and legumes. Much evidence suggests that plant-based proteins are more beneficial for patients with poor kidney function. How much protein does a tumor patient need? Patients with tumors need to consume more protein compared to healthy people. Typically, most tumor patients consume about 1 gram of protein per kilogram of body weight per day during treatment, i.e., a 60-kg patient should have no less than 60 grams of protein per day. Many patients who are already very thin before the start of treatment have severe depletion of protein reserves and should be supplemented with more. 2, fat Fat is usually divided into two categories, saturated fat and unsaturated fat. Unsaturated fats can be subdivided into monounsaturated fats, polyunsaturated fats, omega-3 fatty acids, omega-6 fatty acids and trans fats. Monounsaturated fatty acids and polyunsaturated fats are superior to saturated fats or trans fats. Monounsaturated fats are mainly vegetable oils such as olive oil, canola oil and peanut oil. Polyunsaturated fatty acids are mainly vegetable oils such as safflower, sunflower, corn, and flaxseed; they are also the main fat component in seafood. Saturated fatty acids, on the other hand, are found mainly in animals, such as meat and poultry, whole-fat low-fat milk, cheese, and butter. Some vegetable oils such as coconut, palm kernel oil, and palm oil are also saturated. Saturated fatty acids will lead to elevated cholesterol and increase the risk of heart disease. Therefore, these foods should be avoided or minimized whenever possible. Cancer patients should limit their daily energy intake to no more than 10% from saturated fatty acids. Trans fatty acids are produced when vegetable oils are artificially processed to form margarine or to shorten the fatty acid chain. Sources of trans fats include fast foods and baked goods made partially from hydrogenated vegetable oils or vegetable shortening. Trans fats are also found in some animal products, such as dairy products. Trans fats can raise the level of “bad” cholesterol in the blood while lowering the level of “good” cholesterol. Studies have shown that trans fats increase the risk of cardiovascular disease and tumors. Therefore, you should minimize the intake of trans fats. 3. Carbohydrates Carbohydrates are the main source of energy for the body. The best sources of carbohydrates – fruits, vegetables and coarse grains – also provide the vitamins and minerals, fiber and phytonutrients needed by the body’s cells. Whole grain roughage including cereals, breads, flours and crackers are rich in carbohydrates. Brown rice, barley, etc. can also be used as a side dish. When choosing whole grain products in the supermarket, look for key terms such as “whole grain”, “whole wheat flour”, “whole oat flour” or “whole rye flour”. whole oat flour” or “whole rye flour”, etc. Other sources of carbohydrates are bread, potatoes, rice, pasta, macaroni, cereal, corn, peas and beans. Sweets (desserts, candies, sugar for beverages) also provide carbohydrates, but contain few vitamins and minerals. There are three types of carbohydrates: complex carbohydrates (e.g., vegetables, nuts, seeds, beans, and whole grains), simple carbohydrates (e.g., white bread, a variety of starchy foods), and a variety of sugars (e.g., white sugar, brown sugar, honey, sugar-sweetened beverages, and desserts). All carbohydrates are broken down into sugar in the small intestine and then absorbed by the body, which in turn raises blood sugar levels. The body regulates blood sugar levels by producing insulin. Studies have proven that increased insulin levels will increase the risk of tumors. Although all carbohydrates are eventually broken down into sugar, different foods are not broken down at the same rate. Carbohydrates are categorized by their “glycemic index”, which is based on how quickly and how high a change in blood glucose occurs after food intake. Foods with a high glycemic index, which can raise blood glucose quickly and significantly, include foods that are highly processed to remove bran or hulls, etc. Whole grains, on the other hand, have a higher absorption rate. Whole grains, for example, are absorbed more slowly and have a slower effect on blood glucose levels, making them low glycemic index foods. Consuming both protein and fat affects the rate at which carbohydrates are broken down, which in turn affects the rate at which blood sugar rises and how much insulin fluctuates. For example, the addition of butter to bread will help reduce the magnitude of the blood glucose rise, whereas many sweet carbonated beverages often raise blood glucose quickly, leading to a rapid increase in insulin levels.