Balanced diet refers to the simultaneous establishment of a balanced relationship between dietary nutrient supply and the physiological needs of the organism in four areas, namely: amino acid balance, balance of caloric nutrient composition, acid-base balance and balance between the intake of various nutrients, to not be deficient, not biased, but not, not chaotic, and only in this way will be conducive to the digestion, absorption and utilization of nutrients. If the relationship is imbalanced, that is, the diet is not adapted to the physiological needs of the human body, it will have an adverse effect on human health, and even lead to certain nutritional diseases or chronic diseases. (1) Amino acid balance The nutritional value of food proteins depends largely on the number and proportion of the eight essential amino acids contained in the food, and only when the number and proportion are close to the needs of the human body can tissue proteins of the human body be synthesized. The opposite will affect the utilization of protein in food. The World Health Organization has proposed a ratio of the 8 essential amino acids required by the human body, and the closer the ratio is to it, the higher the physiological value. When the physiological value is close to 100, i.e. 100% is absorbed, it is called a total amino acid balance. Proteins that achieve full amino acid balance are called complete proteins. Using this criterion, amino acid scores can be assigned to the proteins of various foods. Eggs and human milk have amino acid ratios that are very close to those of the human body, so they can be called amino acid balanced foods. Most foods, however, have an unbalanced amino acid profile, so the nutritional value of proteins is affected. For example, too much leucine in corn affects the utilization of isoleucine, and too much arginine in millet affects the utilization of lysine. Therefore, plant-based diet, should pay attention to the rational mix of food, to correct the imbalance of the proportion of amino acid composition. For example, mixing cereals with legumes to make soybean cornmeal, soybean millet flour, etc., can improve the utilization of protein and nutritional value. Food Protein Amino Acid Composition Score Food Amino Acid Composition Score Human Milk 100 Eggs 100 Milk 95 Soybeans 74 Rice 67 Peanuts 65 Millet 63 Wheat 53 Sesame 50 (2) Balance of Caloric Nutrient Composition Carbohydrates, fats, and proteins can provide the body with calories, and therefore are called caloric nutrients. The key to a balanced diet depends not only on the intake of these three nutrients, but also on the balance of the ratio between them. It is generally recognized that 60-70% of the body's caloric energy comes from carbohydrates, 10-15% from proteins, and 20-25% from fats. According to this composition ratio, and taking into account the difference in energy production of different nutrients (1 gram of protein or sugar can produce 4 kcal, 1 gram of fat can produce 9 kcal), the ratio of the three major calorie nutrient intake of food is: carbohydrate: protein: fat = 6:1:0.7. When dietary fat calories are provided too much, it will lead to obesity, hyperlipidemia and heart disease. When protein calories are provided too high, it affects the normal function of protein, causing protein consumption and affecting the nitrogen balance in the body. On the contrary, when the carbohydrate and fat calorie supply is insufficient, it will weaken the protective effect of protein. The three are interacting with each other, once there is an imbalance, it will affect the health of the body. In addition, attention should be paid to the reasonable distribution of calories in three meals a day, with breakfast accounting for 30%, lunch for 40% and dinner for 30%. (3) Balance of intake of various nutrients There is an intricate relationship between various nutrients, and the requirement of nutrients varies with different physiological states and activities, so the Chinese Nutrition Society has formulated the daily supply of various nutrients. The nutrients we consume in our diets are kept within a certain period of time with an error of no more than 10% above or below the standard supply. This ratio between each other can be called the basic balance between nutrients. According to the "Balanced Diet Pagoda", we know that each person should eat (calculated as raw food) 300-500 grams of cereals, 400-500 grams of vegetables and fruits and 100-200 grams, 125 grams of fish, poultry, meat, eggs and other animal foods (50 grams of fish and shrimp, 50-100 grams of poultry, 25-50 grams of eggs), 100 grams of dairy foods, 100 grams of soybeans, 100 grams of milk foods, 100 grams of dairy foods, 100 grams of soybeans, and 100 grams of milk foods. , 100 grams of dairy foods, 50 grams of beans and soy products, and no more than 25 grams of fats and oils. (4) Acid-base balance Under normal circumstances, human blood, due to its own buffering effect, p H value remains between 7.3-7.4. People consume the right amount of acidic food and alkaline food, will maintain the acid-base balance of body fluids, but food, if not properly matched, will cause physiological acid-base imbalance. Common acidic foods include: egg yolk, rice, chicken, eel, flour, carp, pork, beef, dried squid, beer, peanuts and so on. Common alkaline foods include: kelp, spinach, watermelon, radish, tea, bananas, apples, strawberries, pumpkin, string beans, cucumber, lotus root, etc. When food is not properly matched and acidic foods are in the diet in excess of the required amount, it leads to acidic blood, deepening of blood color, increased viscosity and, in severe cases, acidosis. It will also increase the consumption of calcium, magnesium, potassium and other ions in the body, and cause calcium deficiency. This phenomenon is called acidic body, which will affect the health of the body. 2 Balanced Dietary Code Nature has provided mankind with a rich variety of food, and the nutrients contained in various foods are very different. Apart from breast milk, no single natural food can provide all the nutrients needed by the human body. A balanced diet must consist of a variety of food combinations in order to meet the needs of health. How to eat a balanced diet? The Chinese Nutrition Society (CNS) has put forward the following eight recommendations: (1) Variety of foods, cereal-based Cereal-based foods are the mainstay of the traditional Chinese diet. Cereal-based foods are the mainstay of traditional Chinese diets. Cereal-based foods are proposed in order to remind people to maintain the good tradition of Chinese diets and to prevent the disadvantages of dietary combinations in developed countries. Coarse and fine, rice, wheat do not always choose milled too fine, because most of the vitamins, minerals and dietary fiber are present in the surface layer of the cereal. (2) Eat more vegetables, fruits and potatoes Vegetables and fruits are rich in vitamins, minerals and dietary fiber. Some fruits are not as rich in vitamins and trace elements as fresh vegetables, but fruits are richer than vegetables in glucose, fructose, citric acid, malic acid, pectin and other substances. Potatoes shout rich starch, dietary fiber, and a variety of vitamins and minerals. China's residents in the last 10 years to eat less potatoes, should be encouraged to eat more potatoes. Diet rich in vegetables, fruits and potatoes, to maintain human cardiovascular health, enhance resistance to disease, reduce the risk of dry eye disease in children and prevent certain cancers play a very important role. (3) Eat milk, beans or their products Milk, in addition to rich in high-quality proteins and vitamins, high in calcium, and the utilization rate is also higher, is an excellent source of natural calcium. China's residents dietary provision of calcium is generally low, on average, only about half of the recommended supply. There are also more patients with rickets in infants and young children in China, which may be related to insufficient dietary calcium. A large number of studies have shown that calcium supplementation for children and adolescents can improve their bone density, thereby delaying the age of osteoporosis; calcium supplementation for the elderly may also slow down the rate of bone loss. Therefore, milk consumption should be strongly promoted. Beans are traditional food in China, rich in high-quality protein, unsaturated fatty acids, calcium and vitamin B1, vitamin B2, niacin and so on. In order to increase the protein intake of the rural population and prevent the adverse effects of excessive consumption of meat in the city, the production and consumption of beans, especially soybeans and their products, should be vigorously promoted. (4) Eat an appropriate amount of fish, poultry, eggs and lean meat, and eat less fatty meat and meat and oil A considerable portion of the urban population and the vast majority of rural residents in China do not eat enough animal food on average, and their intake should be increased in moderation. However, some residents of large cities eat too much animal food, eat cereals and vegetables are not enough, which is not good for health. Fatty meat and meat oil for high-energy and high-fat food, excessive intake often causes obesity, and is a risk factor for certain chronic diseases, should be eaten less. At present, pork is still the main meat of our people, pork fat content is high, to appropriately reduce the proportion of pork consumption. Promote eating more animal food with less fat content, such as chicken, fish, rabbit, beef and so on. (5) The amount of food and physical activity should be balanced to maintain a suitable body weight The amount of food and physical activity are the two factors that control body weight. Food provides the body's basic metabolic energy and physical activity consumption of energy. If the amount of food is too large and insufficient activity, excess energy will be in the body in the form of fat that is to increase body weight, over time will be fat; on the contrary, if the amount of food is not enough, labor or exercise is too large, due to lack of energy caused by thinning, resulting in a decline in the ability to work. So people need to maintain a balance between the amount of food and energy consumption. Brain workers and people with less activity should strengthen exercise and carry out appropriate activities, such as fast walking, jogging, swimming and so on. Children who are wasted, on the other hand, should increase their food intake and fat intake to maintain normal growth and development and appropriate body weight. Excessive or low body weight is an unhealthy manifestation, which can result in decreased resistance and susceptibility to certain diseases, such as chronic diseases in the elderly or infectious diseases in children. Regular exercise will enhance the function of the cardiovascular and respiratory systems, which will help maintain a good physiological state, improve work efficiency, regulate appetite, strengthen bones and prevent osteoporosis. We advocate that the distribution of three meals a day should be reasonable, generally the energy of breakfast, lunch and dinner accounted for 30%, 40%, 30% of the total energy is appropriate. (6) Eat light meals with less salt Eat light meals conducive to health, not too greasy, not too salty, not too much animal food and fried, smoked food. At present, urban residents have excessive salt intake, the average value is more than twice the value recommended by the World Health Organization. Epidemiological investigations have shown that sodium intake is positively correlated with the onset of hypertension, and thus the amount of salt should not exceed 6 grams. Sources of dietary sodium other than salt include high sodium foods such as soy sauce, pickles, monosodium glutamate, and processed foods containing sodium. The habit of eating meals with less salt should be developed from an early age. (7) Alcohol consumption should be limited People often drink alcohol during holidays, celebrations and social occasions. High alcohol content is high in energy and contains no other nutrients. Uncontrolled drinking will reduce appetite and food intake, resulting in a variety of nutrient deficiencies and, in severe cases, alcoholic cirrhosis of the liver. Excessive drinking increases the risk of high blood pressure, stroke, etc., and can lead to an increase in accidents and violence, which is detrimental to personal health and social stability. Alcoholism should be strictly prohibited, and if alcohol is consumed, a small amount of low-grade alcohol can be consumed, and adolescents should not consume alcohol. (8) Eat clean and hygienic food that does not deteriorate When shopping for food, you should choose food that has a good appearance, is free from dirt and impurities, is not discolored or tasteless, and meets hygienic standards, so as to keep a strict eye on the entry of diseases through the mouth. Pay attention to the hygienic conditions of eating, including the eating environment, tableware and the hygienic and healthy conditions of the person who serves the meal. Collective dining should be advocated to share the meal system, to reduce the chance of disease transmission.