There are a lot of roadblocks put in the way to controlling your weight. In the US that on the intake, junk food is readily available while healthy food is a luxury. Conversely, the US working environment suffers from increasingly medieval labor laws[+], limiting one's ability to exercise or live a well balanced lifestyle.
I wouldn't be so eager to say "being obese is dictated by one's actions". It's an equal mix of self-control and an unhealthy environment.
[+]: "Independent contractors", arbitration, union stigma/busting