The normal value of BMI is usually between 18.5~23.9kg/m2. BMI refers to Body Mass Index, which is an international indicator used to measure the ratio of weight to height, and can determine whether a person is thin or fat. The formula for calculating BMI is weight(kg)÷height(m)², usually, BMI between 18.5~23.9kg/m2 is regarded as normal.BMI below 18.5kg/m2 is called underweight, greater than or equal to 24kg/m2 is called overweight, and greater than or equal to 28kg/m2 is called obesity.Whether the BMI is low or high is not conducive to good health, and therefore need to control BMI in the normal range. BMI is not good for health, so it is necessary to control the BMI in the normal range. If you have a low weight, you need to pay attention to strengthen the nutrition in daily life, do not pick food, partiality; for patients with large BMI, you can carry out appropriate exercise to reduce weight.