There is a scientific basis for the old adage “you can tell when you are three years old”. Studies have shown that the first 1,000 days of life, starting with pregnancy, can affect a person’s health for the rest of his or her life, as well as for future generations. In recent years, the new concept of “1,000 days of life” has received more and more attention. From a mother’s pregnancy to the birth of her child, breastfeeding, and the addition of complementary foods afterwards, the total time is about 1,000 days. Of the 37,000 days in a person’s life, 1,000 days may not seem like a long time, but it has a big impact on the whole life. In the earliest 1000 days of life, not only the growth of body tissues, but also the state of internal regulation of the body is formed, which has an important impact on the whole life process and health direction later on. Problems at this stage, such as delayed intrauterine growth, low or high birth weight, lack of nutrition after birth, overfeeding and excessive weight gain, can bring about long-term health risks, including obesity, hypertension, hyperlipidemia, diabetes and even osteoporosis. Breastfeeding is best for infants from 0 to 6 months of age, and after 6 months of age, breastfeeding should be maintained as much as possible and complementary foods should be added until 2 years of age. In general, breastfeeding has the following benefits. It helps mothers to lose weight and prevent diseases. Studies have shown that breastfeeding mothers have better weight recovery at 6 months postpartum compared to artificial feeding mothers under the same conditions. In addition, breastfeeding helps to reduce postpartum depression and also reduces the mother’s risk of breast and ovarian cancer. Prevents the child from being overweight. Breastfed children gain weight slowly, while formula-fed children tend to gain weight faster. This is because formula feeding makes it easier to consume more protein than breastfeeding. Excessive protein intake can increase the concentration of some non-essential amino acids in the blood, which can cause endocrine stimulation and lead to an increased risk of metabolic disease; it can also modulate the feeding center, causing children to develop a stronger appetite and lead to overweight. Reduces the risk of infectious diseases in children. Breastfeeding protects children from infectious diseases, including gastrointestinal infections, neonatal necrotizing small bowel colitis, and lower respiratory tract infections. Children are less likely to be picky and picky eaters. During breastfeeding, the flavorful substances in the food ingested by the mother can be secreted through the milk and then passed to the baby. By sucking the milk, the baby can feel this variety of flavors and is less prone to picky and partial eating when adding complementary foods. Breastfed children are the smartest. Studies have found that breastfed children have higher cognitive scores at 6 to 23 months of age than children who are artificially fed. The advantage of breastfeeding as a child remains when the relevant IQ measurements are taken in adulthood. The longer the breastfeeding period, the better the IQ development will be. The benefits of breastfeeding on children’s IQ development come from two main sources: firstly, the nutritional content of breast milk has advantages; secondly, the act of breastfeeding itself will promote the development of intelligence. Strengthens the child’s immune system and prevents allergies. Most of the proteins in breast milk are synthesized in the mother’s body, which is not enough to cause allergies in children, and will also strengthen the immune system. Small amounts of proteins from the mother’s diet are also present in breast milk, which are digested and much less allergenic, and also stimulate the development of the infant’s immune system. Breast milk contains some immunoglobulin A, which binds to allergens in the infant’s intestine and prevents or prevents allergens from entering the infant through the intestinal mucosal barrier, thus preventing the development of allergic diseases. Breast milk is also rich in oligosaccharide substances, which can help newborns quickly establish a good intestinal micro-ecological environment, which is conducive to a strong and healthy body and reduces the risk of disease. In the case of formula-fed children, this process is much longer and the quality of the intestinal micro-ecological environment eventually obtained is poorer. The early 1000 days of life are short but have a long-lasting impact, and insisting on breastfeeding is an important strategy to ensure balanced nutrition in the early years of life.