The standard weight formula for girls is (height – 70) × 60% (height in centimeters), so we can calculate the standard weight of a 168cm tall girl is about 58.8kg. the standard weight fluctuates up and down no more than 10% for the normal weight range, the normal weight of the girl should be about 52.9-64.7kg. Overweight is defined as 10%-20% above the standard weight, obese is defined as 20% above the standard weight, thin is defined as 10%-20% below the standard weight, and thin is defined as 20% below the standard weight. BMI = weight (kg)/height (m)^2, 18.5-23.9 as the normal range, BMI <18.5 is called weight Underweight, BMI ≥ 24 is called overweight, BMI ≥ 28 is obese. Low weight in women may cause hair loss, memory loss, osteoporosis and other adverse effects, but also can cause a series of symptoms such as low estrogen levels, affecting fertility. Overweight or obesity can increase the risk of hypertension, diabetes, atherosclerosis, fatty liver and other diseases, so the weight should be controlled within the normal range. It is recommended that those who are underweight should be actively supplemented under the guidance of a doctor. Those who are overweight should lose weight by controlling diet and enhancing exercise. Do not diet to lose weight, which will not only cause nutritional deficiency of the body, but also rebound quickly and cause metabolic disorders, affecting normal menstruation and other physiological functions.