I also agree with the others. Culture plays a big part on the level of obesity among different ethnic groups, people from various states and even among different social and economical classes. As others have already suggested, there is a lot of research and information out there to look at and confirm this.
Yes culture can play a big role in obesity, no doubt about it. Individual states may have different cultural norms based on their environment, their politics, the societal values, social structures and genetic make ups. Norms play a big part in what is acceptable behavior and what is not. As obesity is mostly a preventable condition it is effected by societal norms.