UCLA

A growing literature in public health has suggested that the local food environment influences food choice and obesity outcomes. This dissertation recognizes the importance of the food environment as a potential determinant of health behaviors and health outcomes. These studies examine how the farmers' markets and the workplace food environment impact dietary behaviors and obesity.

Chapter 2 examines the associations between the presence of a farmers' market near home and dietary behaviors among adults in California. It also aims to address whether the selection effect is influencing the relationship between farmers' markets and dietary behaviors. Using data from the 2005, 2007, and 2009 California Health Interview Survey and the locations of Certified Farmers' Markets, this study tested the association of farmers' markets near home with obesity and dietary behaviors, using (1) a directed acyclic graphical causal approach, and (2) a cross-year variation in farmers' markets to control for selection. Results suggest that, adjusting for demographic characteristics, survey year, and the presence of farmers' market during both the current survey year and other survey years, adults living near a farmers' market are less likely to be obese and more likely to eat three or more servings of fruits and vegetables per day. Living near a farmers' market was not significantly associated with soda consumption. This study suggests that locating new farmers' markets in areas with low demand for fruits and vegetables would increase healthy dietary habits.

Chapter 3 tests the associations between farmers' markets near home and fruit and vegetable consumption among adults in California. It also aims to address whether farmers' markets influence fruit and vegetable consumption through the mechanism of increasing perceptions of availability of fresh produce. Using data from the 2011-2012 California Health Interview Survey and the locations of Certified Farmers' Markets, this study examines the impact of farmers' markets on a population level by testing the relationship between farmers' markets upon fruit and vegetable consumption, via perceived availability of fruits and vegetables. Four sets of logistic regressions were conducted to examine this relationship. Farmers' markets were positively associated with perceived availability of fresh produce. Both perceived availability of fresh produce and presence of a farmers' market were independently associated with increased fruit and vegetable consumption. However, when both variables were included in the model, the magnitudes of the associations were very similar. This similarity reflects the weak association between farmers' markets and perceived availability in the sample. The weak association between farmers' markets and perceived availability suggests that the principal pathway for the impact of farmers' markets on consumption is not through increasing perceptions of availability but something else. Regardless, farmers' markets are a useful strategy in promoting consumption of fruits and vegetables.

Chapter 4 studies an area of the food environment relatively unexplored by researchers--the workplace food environment. Using data from Wave 2 of the Los Angeles Family and Neighborhood Survey (LAFANS), a longitudinal, population-based survey of individuals living in Los Angeles County and 2007 Los Angeles County Department of Public Health food outlet data, this study examines the association of the food environment around the workplace with obesity and dietary behaviors among adults. Results suggest that, adjusting for demographic characteristics, the workplace food environment is associated with obesity. There were no significant associations between the workplace food environment and dietary behaviors. The relationship between the workplace food environment and obesity appears to taper off as the food environment becomes saturated with unhealthy food outlets. Further research is needed to understand the relationship between the workplace food environment and obesity and dietary behaviors.