Suggestion: After finding out the cause, deal with the symptoms. If you eat less, it is recommended to use Chinese medicine to recuperate. If you consume too fast, let him reduce his activities appropriately and take blood-enriching drugs in time for anemia. Pay attention to children's balanced nutrition, don't be partial to food, eat more foods that strengthen the spleen and replenish qi, strengthen the spleen and stimulate appetite, and promote digestion, such as japonica rice, coix seed, millet, yam, lentils, potatoes, mushrooms and so on. Eat more fruits and vegetables to supplement vitamins, prevent children from eating snacks and getting more sunshine. If you want to gain weight, in addition to eating meat, eggs, poultry and so on. You should eat more foods rich in fat and carbohydrates, and eat more soy products, vegetables and fruits.