In recent years, China’s rapid economic development, people’s living standards continue to improve, the dietary structure has changed greatly, the increase of indoor sedentary time, physical activity is decreasing, the prevalence of obesity is rising sharply. 2002 national survey of a large sample of overweight and obese people showed that the combined prevalence of overweight and obesity among adults over 18 years of age in China was over 20%. A number of recent local epidemiological surveys show that the combined prevalence of overweight and obesity is higher than 30%, and in some developed cities it even exceeds 50%. Once considered a problem only in high-income countries, the rapid prevalence of overweight and obesity in low- and middle-income countries, especially in urban settings, should be of great concern to society. Lulu Chen, Department of Endocrinology, Wuhan Union Medical College Hospital There are several methods to assess obesity: i. Body mass index (BMI). This is the easiest and most commonly used index to assess obesity, and it is calculated as follows: body mass index (BMI) = weight (kg)/height2 (m2). The appropriate BMI range for adults in China: BMI <18.5 for underweight; 18.5 ~ 23.9 for normal; 24.0 ~ 27.9 for overweight; ≥ 28 for obese. Second, the standard weight (IBW). Standard weight (kg) = height (cm) - 105. ideal weight is allowed to fluctuate 10% on the basis of standard weight, such as more than 10% of standard weight should be considered overweight, more than 20% of standard weight should be considered obese. Third, waist circumference (WC) and waist-to-hip ratio (WHR): waist circumference is also one of the important indicators to measure abdominal obesity, usually the length of the narrowest part of the waist after standing on two feet apart, the length of one week around the level of the natural narrowest part of the waist, male waist circumference ≥ 90 cm (2 feet 7 inches), female waist circumference ≥ 80 cm (2 feet 4 inches) that is obese. Hip circumference refers to the maximum circumference of the hip, waist-to-hip ratio (WHR) of men > 0.9, women > 0.85 that is obese. IV. Determination of body lipid content. This includes skin fold thickness measurement, ultrasonography, CT or MRI, DEXA and so on. These methods require specific instruments and specialized medical personnel to operate. It can accurately detect the distribution and content of body fat, especially for those with thicker bones and more developed muscles, those with excessively short stature or elderly people who cannot accurately measure their height, etc. In addition to a very small number of obese people caused by disease, most of them are simply obese, that is, only obese without any disease obesity. Since this is the case, simple obesity is it possible to ignore and let it develop? The answer is no. Obesity itself is a multi-factor metabolic disease, and obesity-related diseases seriously threaten the health and life of obese people. Ancient people say: the belt is long, life is short, a fat hundred diseases entangled. So what are the hazards of obesity? First of all, obesity is the main risk factor causing cardiovascular, metabolic diseases and respiratory system diseases. Obese people weight overload, heart burden increased, cardiac hypertrophy, while fat deposits in the arterial wall, resulting in lumen narrowing, hardening, prone to hypertension, coronary heart disease, cerebrovascular accidents. Obese people are prone to endocrine and metabolic diseases. Abnormal glucose metabolism can cause diabetes, abnormal fat metabolism can cause hyperlipidemia, fatty liver, abnormal nucleic acid metabolism can cause hyperuricemia, etc.. The imbalance of sex hormone secretion is also associated with the disease, and men show low sexual function and impotence. Women manifest as menstrual disorders, infertility, etc. Obesity is also a high risk factor for sleep apnea syndrome and cancer. Second, obesity affects people’s daily life. People who are obese tend to be afraid of heat, sweaty and easily fatigued, swollen lower limbs, skin folds prone to dermatitis, varicose veins, etc. Seriously obese people, slow action, walking difficulties, a little activity will be panic and shortness of breath, because of its slow response, but also easy to suffer a variety of trauma, car accidents, etc., affecting normal life, and even loss of ability to work. In addition, obesity is also vulnerable to social prejudice and discrimination and other psychological harm. It can be seen that obesity is not only a single disease, it can cause abnormalities of many systems in the whole body through the role of the body and metabolism. Therefore, it is especially important to take effective measures to actively prevent and treat obesity. Secondary obesity caused by other diseases should actively treat the original disease, and for simple obesity healthy living habits is the best treatment means. In the process of eating the energy intake greatly exceeds its own consumption of energy, the excess energy will be fat in the form of accumulation in the body thus appearing obese. Usually do not overeat, dinner as little as possible. Change the bad habits such as eating sweets, snacks, extra meals before bedtime and going to bed immediately after meals. Have a plan for purchasing and cooking, so as not to cause fear of waste and eat more. Try to eat at home and reduce the chances of eating in restaurants. Even if you go out to eat, you can eat some fruits beforehand to increase the feeling of fullness and reduce the amount of meals; choose to eat light dishes rich in fiber, eat less bulky food with high energy, and eat more food that is more troublesome to eat; do not drink sweet drinks and drink less alcohol. At the same time to exercise more. Usually, if time allows, walk instead of riding a bicycle, ride a bicycle instead of taking a car, climb more stairs at work, and integrate exercise into your daily life. You can also choose to run in the morning, walk after dinner, indoor yoga, swimming and other aerobic exercise, it is important to adhere to. In short, learn to eat scientifically, exercise scientifically, and master the balance principle of calories in and out, you can well achieve the purpose of weight loss. In addition to poor lifestyle, genetics is another factor that should not be ignored obesity. For both parents are obese, the possibility of their children obese up to 75% to 80%, while both parents for normal weight, the risk of children obese only 10%. Some obese people complain that “a mouthful of cold water will be fat”, genetic factors may have played a major role. For those who have a family history of obesity, once obesity, weight loss effect than other people without family history will be much worse, should take early and effective measures to prevent the occurrence of obesity. Into adulthood to middle age, with the age of growth, metabolic rate and body hormone level changes, weight is slow growth trend, after middle age weight tends to be stable. Although weight increase is a natural law, but a person from adulthood to old age weight fluctuations in general within 7 kg. Once the signs of overweight or obesity are found, secondary obesity should be ruled out first. If the diagnosis is only simple obesity, the next step should be to further check blood pressure, blood lipids, blood sugar level, abdominal ultrasound and electrocardiogram examination is also necessary. Correct bad habits and strive to return to the ideal weight level. If abnormal indicators appear, lifestyle interventions and close follow-up are sufficient for those with mild abnormalities, and lifestyle interventions supplemented by medication for those who reach the diagnostic criteria. For obesity has appeared a variety of concurrent diseases, feasible drug weight loss treatment. For severe obesity (BMI>40kg/m2), gastric surgery is feasible to reduce the volume of gastric contents, increase the sense of satiety, and reduce body weight by reducing the amount of food eaten. Obesity as a global chronic disease, has been recognized by the World Health Organization as the fifth major risk factors affecting health, and its coexisting diseases have been a serious threat to human health. Promote a healthy lifestyle, correct bad habits, early pre-treatment, and reduce the incidence of overweight and obesity.