BMI, also known as Body Mass Index, is calculated as weight/height². Body Mass Index (BMI) is an indicator commonly used internationally to measure the degree of fatness or thinness of the human body, and is calculated by the formula weight ÷ height², where height is measured in meters and weight in kilograms. The normal value of BMI is 18.5~23.9, 24~27.9 is overweight, and greater than 28 is obese. Lean body types need to increase the amount of food and gain weight in moderation; obesity needs to limit the amount of food and maintain a low-salt, low-fat, low-sugar diet with appropriate exercise. If there is an abnormal BMI value, it is recommended to go to the hospital and ask the doctor to develop an appropriate treatment plan.