I agree that the media is a huge issue in weight perceptions, but so are the ever-prevailing ideas about portion sizes. Here in the US, we've been blessed to have plentiful food for the vast majority of the population -- and most of us had parents or grandparents who worked at physically laborious jobs all day every day, so they had a very different idea of what a good amount of food looked like. My mom was raised on a ranch, and I was raised on a farm -- you eat a large, calorie-laden meal in the morning so that you can work non-stop until evening, with only a fast standing meal in-between for lunch. People have continued to eat like this, even while they sit in office chairs all day, or stand around helping customers, or even stock shelves and things that might be higher-impact, but far from back-breaking. Add to that, many people in the US prefer to find something else to blame for their weight issues (i.e. stress, over-processed food, etc.) rather than taking responsibility for their own health and well-being.
This isn't a judgmental statement, I was there relatively recently myself, but I do think there is nothing quite so sickening as a country that is habitually over-fed and upset about it, while so many people in the world barely have enough food to stay alive. The most important muscles to develop first are the triceps and biceps -- instrumental in pushing the plate away. As long as we buy the over-processed food, the companies will continue to market them and push for their sale -- supply and demand, do with it what you will.