Contributing factors to obesity in modern life: overeating, reduced physical activity, and the social contagion effect.

Environmental factors

(a) Overeating

With economic development and increasingly abundant food supplies, people can easily obtain the food they want, leading to excessive energy intake and relatively insufficient energy expenditure. If daily energy intake exceeds energy expenditure by just 200 kcal, this can amount to an extra 6000 kcal per month, potentially resulting in an increase of 1-2 pounds of body fat. The 2002 China Nutrition and Health Survey surveyed over 40,000 middle-aged individuals, categorizing their energy intake into high, medium, and low levels, and analyzing their relationship with overweight and obesity.

The results showed that compared with the low-energy intake group, the risk of overweight and obesity was 14% higher in the moderate-energy intake group, and the risk was 34% higher in the high-energy intake group than in the low-energy intake group. In times of war and famine, who has ever seen so many obese people? The incidence of obesity is higher in economically developed countries than in developing countries, and the incidence of overweight and obesity is higher among urban residents than in rural residents in my country. These findings strongly suggest that overeating is an environmental factor contributing to obesity.

(ii) Reduced physical activity

In modern society, mechanized operations have replaced heavy physical labor, and commuting by car has replaced walking. The use of vacuum cleaners, washing machines, and other appliances has greatly reduced the burden of housework. Many people spend eight hours a day in front of a computer, then return home to play video games or watch TV on the sofa – this has become a habitual lifestyle. The decreasing energy expenditure coupled with increasing energy intake, resulting in a long-term energy imbalance, inevitably leads to rapid weight gain.

A large-scale health survey in my country indicates that the longer one spends in sedentary activities (such as watching TV, using a computer, or reading), the higher the prevalence of overweight and obesity. People who spend more than four hours a day in sedentary activities have twice the prevalence of overweight and obesity, and a 50% and 18% higher prevalence of diabetes and hypertension, respectively, compared to those who spend less than one hour in sedentary activities.

(III) Social Impact

Increased competition for jobs and busy work schedules have left people with little time to prepare meals at home. Coupled with the influence of commercial advertising, this has led to a rise in the proportion of high-fat, high-energy fast food in their diets. Many business negotiations take place in restaurants, contributing to the beer bellies of many self-proclaimed "successful people." Due to misconceptions about what constitutes health, people often equate obesity with robustness and health, especially with infants and children. The phrase "What a chubby little boy!" is a compliment for infants, suggesting that heavier infants are less prone to illness and easier to care for.

In Chinese folk customs, gatherings and banquets are indispensable for weddings, funerals, festivals, reunions with friends, and promotions. On these occasions, food intake increases significantly, with large amounts of meat and alcohol providing high energy levels. You might be surprised to learn that obesity is a contagious disease. A July 2007 study published in the *New England Journal of Medicine*, based on a survey of over 10,000 people, found that if someone's close friend is obese, their chances of becoming obese increase by more than 50%; if someone's siblings are obese, their chances of becoming obese increase by 40%.

Of course, the "contagion" referred to here is not through viruses or bacteria, but rather a social infectious disease. If many people around a person are gaining weight, they gradually become accustomed to obese bodies, and their perception of acceptable body types changes subtly. Consequently, they become less vigilant about their own gradual weight gain. The above research results emphasize that people should be encouraged to control their diet and exercise with family and friends.

(iv) Psychological factors

When faced with various psychological pressures, people often use food to relieve them. For example, Oprah Winfrey, the famous American talk show host who recently retired, recounted in her book how, when she was first transferred to Baltimore as a news anchor, she had to endure the loneliness of living alone in an unfamiliar city and the pressure of lacking confidence in her new role. So every night, she would go to the grocery store and stuff herself to the brim, spending a happy time eating before going home to sleep. She gained 5 kilograms in two weeks.

These facts demonstrate that changes in living conditions, such as abundant food supply and reduced physical activity, played a dominant role. Even if you are genetically more prone to weight gain than others, you can definitely lose weight if you are determined to change your lifestyle.