BMI, also known as body mass index, is an indicator used to assess physical health, which is calculated by dividing weight (kg) by the square of height (m). The normal value of BMI is between 18.5 and 23.9. If it exceeds 24, it is considered overweight; if it exceeds 28, it is considered obese, and if it is lower than 18.4, it is considered emaciated. For example, an adult weighing 70kg with a height of 1.74 meters calculates BMI=70➗(1.74^2), which results in a calculation of 23.12, which is in the normal range, indicating that the weight is within a reasonable range. Overweight or obesity may lead to excessive accumulation of body fat, which tends to increase the chance of diseases such as coronary heart disease, diabetes mellitus, hypertension and hyperlipidemia. Underweight is prone to malnutrition and other conditions. Therefore, we should actively control our weight and keep it within a normal range, which is most beneficial to our body.