1. Genetic factors: most of them are considered as "multifactorial inheritance". When parents inherit their children's physique, it is not one genetic factor but many genetic factors that determine their children's physique, so it is called multifactorial inheritance, such as non-insulin-dependent diabetes and obesity, which belongs to this kind of inheritance. If one parent is obese, their children have a 40% chance of being obese. If both parents are obese, the probability that the child may be obese will rise to 70%-80%. There are few examples of "multifactorial inheritance", but there are many examples of parents' "wrong eating habits" leading to obesity.

2. Social and environmental factors: Many people have the concept that "eating is happiness". In today's society, there are many kinds of delicious food, and all kinds of delicious food often tempt you. In addition, "eating a big meal" has almost become a common entertainment, which of course has become the main cause of obesity.

3. Psychological factors: In order to alleviate emotional distress and emotional instability, many people also use "eating" to vent. These are the causes of overeating and obesity.

4. Factors related to exercise: Exercise helps to burn fat. In daily life, with the development of transportation, the mechanization of work and the reduction of housework, there are fewer and fewer opportunities for human body to consume calories. On the other hand, because the energy intake has not decreased, it has become obese. Obesity leads to the slowness and laziness of daily activities, and reduces the consumption of calories, leading to a vicious circle and contributing to obesity.