Why do governments pursue obesity legislation? And is the case of Brazil unique compared with other nations when considering the politics of policy reform? Using a nested analytic approach to comparative research, I found that theoretical frameworks accounting for why nations implement obesity legislation were not supported with cross-national statistical evidence. I then turned to the case of Brazil's response to obesity at three levels of government, national, urban, and rural, to propose alternative hypotheses for why nations pursue obesity policy. The case of Brazil suggests that the reasons that governments respond are different at these three levels. International forces, historical institutions, and social health movements were factors that prompted national government responses. At the urban and rural government levels, receiving federal financial assistance and human resource support appeared to be more important. The case of Brazil suggests that the international and domestic politics of responding to obesity are highly complex and that national and subnational political actors have different perceptions and interests when pursuing obesity legislation.