Nutritionists tell us that there are three basic nutrients in balanced nutrition: protein, carbohydrate and fat. In addition, there are vitamins, minerals, cellulose and so on. The following nine nutrients are usually listed as essential nutrients, and their main food sources are: 1. Protein: Poultry, meat, fish, beans, eggs, cheese, nuts, melon seeds and so on. 2. Carbohydrates (sugar): cereals, potatoes, corn, dried beans, sugar, etc. 3. Fat: edible oil (including butter, margarine, etc. ), fat meat, sausages, nuts, melon seeds, peanuts, etc. 4. Vitamin A: animal liver, carrots, tomatoes, sweet potatoes, green leafy vegetables, cream, etc. 5. Vitamin C: cauliflower, citrus, papaya, mango, strawberry, cabbage, potato, tomato, green leafy vegetables, etc. 6. Vitamin B 1: lean meat, nuts, coarse grains, staple and non-staple foods (such as coarse bread and fortified grains). 7. Vitamin B2: animal liver, milk, yogurt, green leafy vegetables, coarse grains, food, etc. 8. Calcium: milk, yogurt, sardines, boneless salmon, meat rolls, vegetables, mustard, radish leaves, etc. 9. Iron: beef and mutton, animal liver, green leafy vegetables, dried beans, mung beans, coarse grain products, etc. Balanced nutrition is the most beneficial to health. Generally speaking, every meal should be dominated by 50% grains, including rice, millet, corn, flour and potatoes. Vegetables and fruits account for about 20%, of which vegetables account for 3/4 and fruits account for1/4; Bean products are rich in protein and vitamins, which should be eaten every day, accounting for about15% of the total intake; Meat and eggs, including fish, chicken, pork (lean meat), beef and eggs, account for about 5% of the total intake; The remaining 10% is best composed of dairy products, fat and sugar, seeds and hard-shelled fruits can provide beneficial fat, and honey and unrefined sucrose are the best sugary foods. As can be seen from the sources of the above nutrients, the essential nutrients for the human body can only be obtained through a variety of foods. Therefore, in addition to flour and rice, it is best to eat miscellaneous grains (such as potatoes) as daily staple food. Non-staple food should be done well, and half of vegetarian dishes are green leafy vegetables. If possible, milk and fruit should be supplemented. In this way, it is easy to obtain comprehensive and balanced nutrition if the diet is diversified and not partial eclipse. Of course, not partial eclipse is not absolute. For example, strong mental workers can supplement their brains with food and eat more animal foods such as milk, eggs, animal hearts, livers and brains. They need to contain protein, essential amino acids, phospholipids, iron, calcium, phosphorus and vitamins, which is of great significance to the development and health care of the brain. There are also brain-nourishing foods in plants. Soybeans and corn are the first choice. Soybean is rich in plant protein, and corn is rich in fat, calcium, phosphorus, iron and other inorganic salts and glutamic acid, which can promote the metabolism of brain cells. In addition, jujube, walnut and other fruits also contain high content of protein, sugar and phosphorus, which can nourish the brain. For beauty, food also plays a great role. For example, eating more foods containing vitamin A can lubricate and strengthen skin function and prevent dryness. Eating more foods containing vitamin B can prevent constipation, soothe the nerves and strengthen the heart; Eating more vitamin C can keep skin smooth and elastic, prevent aging and scurvy, and so on.