Understanding changes in diet, physical activity and weight among adults in China

China is facing a growing overweight problem in its adult population. This is a worrisome trend given its population size and the potential health care costs associated with nutrition-related non-communicable diseases. This trend has occurred together with changes in China's economic, social and physical environment. Hence, it is important to consider these factors in trying to understand what determined the changes in diet and physical activity, and thus the increases in weight. This dissertation first looks at how various dimensions of urbanization are associated with declines in physical activity. Second, it addresses how price and income changes might have contributed to dietary changes over time. Third, I apply a dynamic panel model to determine the degree to which physical activity and dietary choices affect weight change over time.;I found that physical activity declines are strongly associated with greater availability of higher educational institutions, housing infrastructure, sanitation improvements and economic well-being of the community in which people function. These urbanization factors are associated with four-fifths and two-third of the decline in occupational physical activity for men and women, and 57% and 40% of the decline in total physical activity for men and women, respectively. Looking at food consumption, I found that changes in price elasticities are complex and are food-group and income-specific; income elasticities have fallen for most food-groups; rice has become an inferior good; and that the demand for pork was the most income responsive of these food-groups. I also found that dietary fat intake and declines in physical activities are positively related to weight gain among men, and that 30% of the weight gain was due to declines in physical activity, while 20% was due to higher fat intake. Given the rising overweight and obesity rates in China, these results suggest that policymakers should consider solutions targeting both physical activity and diets, as affected by the built and economic environment.