This Article constructively critiques the two arguments that public health advocates have made in support of antiobesity soda taxes or junk food taxes. Part II discusses and critiques the first argument, an economic externalities argument that government should tax soda or junk food to internalize the disproportionately high health care costs of obesity. Part II also explores an alternative economic internalities argument for food or soda taxes, with a focus on incomplete information, bounded rationality, and bounded willpower. Part III discusses and critiques the second argument made by public health advocates, that government should adopt antiobesity measures to improve population-wide health. This Part considers the appropriate scope of public health law interventions with respect to behavioral risk factors (for example, diet), comments on empirical evidence offered by public health advocates to support proposed soda taxes, and cautions public health advocates to consider possible unintended consequences of antiobesity proposals. Obesity policy debates present a conflict of fundamental values, such as health, fairness, efficiency, and autonomy. Part IV attempts to reconcile these values and responds to the “personal responsibility” objection to soda taxes and food taxes. Part V considers various factors that would affect behavioral responses to proposed soda taxes and food taxes and addresses concerns that such taxes would be regressive and thus unfair to low-income consumers. This Part also explores the tax design implications of the literature on tax salience and on asymmetric paternalism and libertarian paternalism. Part VI suggests the way forward for public health advocates, including a proposal to enact a tax on nutritionally poor foods and drinks, paired with a salient benefit. This Part also recommends enactment of a federal system of food classification, based on nutrient-profiling methods, along with a federal system of front-of-package nutritional labeling.