This dissertation presents a series of empirical studies to evaluate the effectiveness of soda taxes to curb the obesity epidemic. Chapter 1 describes the extent and severity of the obesity problem in the U.S., and discusses the policy interventions that have been proposed or enacted with the intent to fight obesity (e.g., sales taxes). Chapter 2 contains a study on the effect of two tax events on soda consumption: a 5.5% sales tax on soft drinks imposed in Maine in 1991, and a 5% sales tax on soft drinks levied in Ohio in 2003. We investigate this question by using sales data collected by scanner devices in Maine, Massachusetts, New York and Connecticut, as well as Ohio, Illinois, Michigan and Pennsylvania. Results suggest that these sales taxes had a statistically insignificant impact on the overall consumption of soft drinks. Chapter 3 describes an empirical study that looks at whether the 5% sales tax on soft drinks in Ohio in 2003 had a differential impact on different socio-economic segments of the population. In line with the results described in Chapter 2, this study suggests that the impact of a tax had a homogeneous effect (and statistically insignificant) across different demographic groups. In Chapter 4 we investigate whether the demand for soda varies with the obesity rate. To this end we develop a demand model that is able to incorporate dynamic properties of this market as well as the resulting possibility that the obesity rate might alter the parameters of the model.