Many parents have the notion that although my child is a little bit fat, it means that my child is well nourished and good nutrition is good for the growth and development of the child. In fact, this view is incorrect. Childhood obesity can bring a series of problems to growth and development. Early childhood obesity can delay the start of walking, and because of excess weight and calcium deficiency, deformities such as knee valgus (X-leg), knee inversion (O-leg) and flat feet can easily occur. Early fat will also accelerate the growth of bones, resulting in early bone age, which may lead to premature stagnation of bone development, premature closure of the epiphysis, so that obese children appear to be taller than others when they are small, but slow to grow when others leap, but the final head is not as normal weight children. In the body of fat children, the level of growth hormone is not high, or even low, while the level of free insulin-like growth factor-1 increased, which may be the reason for the rapid growth of fat children as children. Obesity also has a great impact on youth development Obese girls may have early puberty, breast development and early onset of menstruation. However, they are instead prone to ovulation disorders, poor egg development and low estrogen and progesterone levels in adulthood, resulting in infertility. The situation is more complicated in boys. Obese boys can develop precocious puberty and possibly delayed pubertal development. Severe obesity is more likely to retard the pace of pubertal development. Mammary gland development is the biggest trouble for obese boys. Many normal boys also have breast development at puberty, but it is not severe and it resolves on its own within 2-3 years. The rate of breast development is significantly higher in obese boys than in normal boys, and the age of remission is also greater. In addition, obese boys are often seen to have atrophied testicles, a short penis, and a poorly developed prostate, and such children are prone to sexual hypogonadism when they grow up. The cause of abnormal pubertal development in fat children is not clear.