158 girls refers to girls with a height of 158cm, and their standard weight can be calculated based on height or body mass index. When calculated by height, according to the World Health Organization standard, weight (kg) = [height (cm) – 70] × 0.6, the standard weight can be obtained as 52.8kg, in the standard weight ± 10% range are normal weight, that is, 47.5kg-58.1kg. another algorithm is based on the body mass index, according to our standard, body mass index 18.5-23.9kg/m^2 for Normal, body mass index (kg)/height squared (m^2), the calculation can be obtained 158cm girls normal weight range is 46.2-59.7kg. two algorithms obtained range is not a big difference, can be used as a reference. If the girl is a long-term exercise, muscular condition, or the body is in a pathological state of water retention, the real weight may exceed the calculated one. Besides, the weight obtained from these two calculations can be used to measure the nutritional status of the body of wasted, overweight or obese. According to WHO standards, a body mass index <18.5 kg/m^2 is considered wasting, ≥25 kg/m^2 is overweight, and ≥30 kg/m^2 is obese. Wasting may be caused by excessive weight loss, digestive system diseases or other diseases, mostly due to poor digestion, which causes nutrients in food not to be absorbed by the body and directly excreted, or due to other factors that increase body consumption, all of which can lead to underweight. It is recommended to seek medical examination to exclude disease factors. Overweight or obesity is mostly caused by improper dietary habits, but can also be caused by endocrine disorders and drug side effects. Overweight can increase the incidence of hypertension and diabetes. Weight should be actively controlled and abnormalities should be intervened in time to avoid aggravating the condition.