The aim of this article is to analyze the conceptual structure underlying the models of obesity prevention implemented in Argentina, Brazil, and Spain. In their culturally distinct but epidemiologically similar contexts, the three countries have devised strategies that reproduce global diagnoses of the causes of obesity and replicate some of the measures proposed at the global level. While so-called “obesogenic environments” are considered primarily responsible for these tendencies, efforts to raise awareness about food and nutrition tend to promote self-monitoring and behavior rationalization as the main tools for achieving changes in diet and physical activity. Although a variety of measures have been proposed at the local level, they have been less diverse in terms of their nature and scope, barely taking into account the constraints that hinder the adoption of healthy lifestyles. In contexts of social and food precarity, this has meant neglecting the social groups with the highest prevalence of obesity.