With long-term poverty and famine in the last century, the Chinese had a traditional view that fatness represents abundance and happiness [6] . Beliefs have not kept pace with the changes in socioeconomic status and have led to overconsumption and energy imbalance of food. The policy of one child made the whole family overfeed their only child and increased the prevalence of obesity and overweight [6] . Min’s research shows that children who were only children had approximately four times the likelihood of being overweight or obese compared to those with brothers or sisters (OR = 4.53, 95% CI: 1.65 - 12.40) [25] . Research also shows that parents would like to spend money rather than take time to look after their children, which leads to children eating food with high energy, high sugar, and high fat [26] . With increasing screen time on mobile media devices, children were more likely to eat more while they watch media. Screen media exposure increases the energy intake of children [27] . Sleep deprivation was also associated with childhood obesity. Inadequate sleeping time might change the hormonal level, which affects the appetite and satiety of children [3] . Some cross-sectional studies showed that there was a relationship between sleep duration and overweight. People who sleep less than 9 hours per day would have 3.8 times the likelihood than people who sleep 11 hours to be overweight and obese [28] .

Also, excess energy consumption during media device use can lead to obesity [29] . As an increasing number of children spend time on their mobile devices, they lack physical activity. In addition, they may be exposed to incorrect information, which can lead to unhealthy lifestyles [3] . Children are now exposed to marketing in new media, including websites, apps, and games sponsored by food companies [29] . Some studies have shown that food advertising will impact food preference and food intake in children. In Xian’s research, around 20% of the children would request their parents to buy advertised foods [30] . Most children under six years old cannot distinguish between television programming and advertising [3] . Additionally, there are many product placements for television programs. Children tend to buy food shown on television because they think it will be cool [3] . Food advertising impacts the dietary habits of children because they always show low-nutrition food, which contains higher energy and saturated fat [3] . Also, children who watch television and use mobile phones frequently are more likely to eat potato chips and sweetened soft drinks. There is also some evidence that there is a relationship between TV time and extra energy intake [3] . Some meta-analyses have shown that the risk of obesity among children will increase by 13% as they watch television every additional hour per day [27] . The food companies provide more food that contains high energy and saturated fat, and children cannot resist the temptation [31] . However, it can also harm children’s health. Children are more likely to consume these foods than fresh vegetables and fruits in their daily lives. It is essential to establish regulations and policies on food labelling, fast food expansion, and marketing and to educate children on nutrition knowledge.

The community environment may have an indirect influence on children’s health status [3] . With urbanization, there are more processed foods that contain high energy-dense and sweetened. Fast food restaurants are popular among children, and they are always near the school. The type of food vendors in a neighbourhood will impact people’s eating habits [3] . For instance, if there are more fast-food restaurants and snack food stores in a community, the residents may have more risks of being obese [32] . In some schools, the retail store will sell many kinds of snacks and drinks [19] . Drinking too many sugar-sweetened beverages will gain weight and may lead to type 2 diabetes (T2D). It is interesting to find that the community where near the supermarkets will have a lower prevalence of obesity compared to the areas that do not have malls or supermarkets. The main reason may be that the residents can easily get fresh fruits and vegetables every day and will not need to store large amounts of food [33] . When food is available and high-quality, people’s food types may change. Also, the price of food can impact the food pattern, and socioeconomic status is also a factor that affects people’s food choices [24] . The reason why the prevalence of obesity among some socioeconomically disadvantaged groups becomes higher may be that fresh fruits and vegetables may be expensive to them, so they tend to choose food with lower prices. In this case, they are more likely to consume food with energy-dense content, which has poor nutrients.

Evidence shows that children who do not have physical education and a healthy diet will not have an awareness of getting a healthy lifestyle, and they will tend to be obese [34] . Children and adolescents spend more time on homework rather than doing exercises. Sometimes, the school will even cancel the extracurricular physical activities [6] . Ren’s research showed that heavy weekday homework was positively associated with childhood obesity [35] . The family environment will impact the eating patterns of children [36] . In China, children may lack education about obesity and its related harm. Most parents hold the view that children can eat whatever they want, and it does not matter if they eat too much because they need to grow up with energy [3] . Especially some children who are raised by grandparents. The grandparents may not have enough health knowledge, and they spoil their kids [37] . The grandparents commonly have inappropriate perceptions, like the diseases related to obesity can only happen in adults. They may feed their children with much more meat and oil, and they think it is good for children [37] . There is evidence showing that children who live with their grandparents in China are more likely to become obese. In the cross-sectional study, children fed by grandparents had a higher risk of being overweight and obese (adjusted OR = 2.03; 95% CI: 1.19 - 3.47) [36] . Sometimes, the grandparents will give children snacks as a reward when the children behave well [36] [37] . In addition, the grandchildren will be overprotected from doing physical household chores by their grandparents [36] .

For children, although they begin to show a tendency to autonomy in food choices, their eating behaviour is still immature, and they are always influenced by their peers [38] . Sometimes, they will imitate the eating behaviours of their peers, and they cannot distinguish between right and wrong. It may result in them eating more junk foods and less fresh vegetables and fruits [38] . They tend to eat similar foods to their peers and friends, which may not be healthy. Research also showed that if children have a close friend with a high BMI, then their BMI will be the same as that of their friends [39] . This may be because they have the same eating habits and interact with each other.

Some people who migrate to the city may keep their old eating habits. For instance, the only way for people who live in high-altitude pastoral areas to intake salt is by drinking milk tea in the past [19] . However, when these groups of people migrate to the city, they will eat like the urban residents. They add salt when they cook, and they eat snacks that contain high salt. At the same time, they also drink salty milk tea [19] . This kind of eating pattern leads to hypertension and obesity among the group of people [19] . In undeveloped and low-income areas, children may face the phenomenon of the double burden of nutrition [40] . Some children may have a slow-growing development compared to the children who live in the developed areas. However, the nutritional transformation has changed their eating patterns [40] . The children like to eat puffed food and sugar-sweetened beverages, which leads to obesity and overweight. It shows that in some areas, the children may have both malnutrition and overnutrition [40] .

Children who are obese and overweight are more likely to choose energy-dense foods as a lifestyle [19] . Studies showed that BMI is positively related to dietary patterns, which include much more meats, eggs, fats, and oils. There is a negative association between BMI and taking vegetables, beans, fruits, and grains [31] .

In addition, the food preferences of children have a high relationship with their parents’ eating patterns [19] . For instance, if children are exposed to green vegetables frequently and repeatedly, their preference and consumption of this kind of food will increase [41] . What should be mentioned is that if children eat more meals outside, their food preferences will change. The restaurants will provide food that contains more salt and oil to make the meal more delicious [32] .