The rate of obesity has increased noticeably in China since the 1980s, brought about by the "After Mao" revolution. This dissertation examines the social determinants of obesity and weight gain among men and women, using 1991-2009 waves of the longitudinal China Health and Nutrition Survey. The first study emphasizes that rapid technological adoption at home may also have the potential to lead to obesity epidemics. I hypothesize that adopting household technology is a factor in weight gain, independent from daily calorie consumption and energy expenditure in exercise. The results show household technology ownership and weight gain are linked, while changes in overall energy intake and exercise may not function as mediators for this relationship. Future public health policy may evaluate interventions that are focused on increasing low-intensity activities impacted by household technologies. My second study discusses whether obesity wage penalties seen in Western societies, such as wage reductions for obese individuals, are observed in modern China. The results indicate that obese women are not subject to wage penalties, while current male obesity rates may be worsened by heightened economic outcomes and greater social acceptance by customers and colleagues. With increasing interpersonal interactions in the workplace in Chinese industries, and the lack of public awareness of the risks of obesity, Chinese public health strategies for preventing and controlling obesity should target male non-manual laborers, the most vulnerable population in the future. The third study analyzes the impact of parental and own socioeconomic status on adult body weight and extends the research by estimating the influence of intergenerational social mobility on current body mass index. In the context of increasing social inequality in China, the study shows parental SES, own SES, and social mobility to be negatively associated with body mass index among women; while respondent's SES is positively associated with body mass index among men. The study results support the theory that parental SES has a more significant impact on current body weight for men and women after controlling social mobility; indicating that social mobility may function as a mediator for the relationship between parental SES and current body mass index.