BMI refers to body mass index, an international standard for calculating the degree of fatness and thinness of the human body and whether it is in a healthy state through a formula. the formula of BMI = weight (kg)/height (m)^2, the calculated body mass index according to our standard, 18.5-24.9kg/m^2 is normal, 24-27.9kg/m^2 is overweight, ≥28kg/m^2 is obese, and BMI < 18.5kg/m^2 is wasting. However, generally only through BMI, that is, body mass index also can not accurately describe the distribution of body fat, and can not distinguish between fat and muscle content, easy to misjudge the state of health, can be a combination of the following ways to test: 1, ideal weight: ideal weight can be through the height (cm) - 105, and height (cm) - 100 × 0.9 (male) or × 0.85 (female) two formulas Calculation. The general normal ideal weight ± 10%, such as more than 10.0%-19.9% is overweight, more than 20.0% is obese; 2, waist circumference: the subject should stand in a standing position, feet apart 25-30cm, weight evenly distributed, and measure the midpoint level of the line connecting the anterior superior iliac spine and the lower edge of the twelfth rib. Normal waist circumference is usually <85cm in men and <80cm in women; 3. Waist-to-hip ratio: hip circumference measures the circumference of the most prominent point of the pelvis surrounding the hip, and the waist is usually <0.9 in men and <0.85 in women compared to the hip; 4. CT or MRI: If you want to confirm the body fat situation, you can also choose CT and MRI in imaging to assess the body fat distribution; 5. Other : Body fat content can also be determined by body densitometry, bioresistance resistance method, etc. to assess the health status of the body, etc. Being underweight or overweight is not good for health, so if you are underweight, you can improve by gaining muscle and increasing the amount of high protein, high quality fat and high calorie food, such as meat and eggs. If you are overweight, you can reduce your weight by exercising, such as yoga, jogging, swimming, walking, etc., and adjusting your diet to control your calorie intake.