Recently, public health agents and the popular media have argued that rising levels of obesity are due, in part, to "obesogenic" environments, and in particular to the clustering of fast food establishments in Western urban centers that are poor and working class. Our findings from a multi-site, cross-national qualitative study of teenaged Canadians' eating practices in urban and rural areas offer another perspective on this topic, showing that fast food consumption is not simply a function of the location of fast food outlets, and that Canadian teens engage in complex ways with the varied dimensions of choosing (or rejecting) fast foods. Drawing on evidence gleaned from semi-structured interviews with 132 teenagers (77 girls and 55 boys, ages 13-19 years) carried out between 2007 and 2009, we maintain that no easy relationship exists between the geographical availability of fast food and teen eating behaviors. We use critical obesity literature that challenges widely accepted understandings about obesity prevalence and etiology, as well as Lamont's (1992, 2000) concept of "moral boundary work," to argue that teen fast food consumption and avoidance is multifaceted and does not stem exclusively nor directly from spatial proximity or social class. Through moral boundary work, in which teens negotiated with moralistic notions of healthy eating, participants made and re-made themselves as "good" and successful subjects by Othering those who were "bad" in references to socially derived discourses of healthy eating.