The obesity index is usually referred to as the body mass index (BMI), also known as the body mass index or body mass index, which is an important criterion used to measure the degree of fatness and thinness of the human body, as well as whether it is healthy or not. The body mass index is calculated as weight (kilograms) ÷ [height (meters)]². The BMI index for adults in China is <18.5 for underweight, 18.5~23.9 for normal weight, 24~27.9 for overweight, and ≥28 for obesity. It is generally recommended that through diet control, physical exercise and other ways to achieve the purpose of weight loss, the BMI index will be controlled within the normal range; BMI index of less than 18.5 is underweight, it is recommended that the patient to develop good eating habits, appropriate supplementation of the body's required nutrients, to avoid malnutrition, and can also enhance physical exercise, strengthen the physical fitness, and improve the body's immunity. It is recommended that if the patient is not feeling well, he should go to the hospital in time, complete the relevant examinations, clarify the cause of the disease, and choose the appropriate treatment program under the guidance of the doctor, avoiding self-medication and delaying the condition.