[First Respondent] Obesity: Exercise or Calories?

When I read the Hunter-Gatherer Energetic and Human Obesity article that suggest that our expended energy today is not all the different from that of our ancestors, I was pleasantly surprised. No more going out of my way to be "healthy" (aka taking the stairs to the 5th floor of the building where I live as opposed to just taking the elevator). The article made it clear that regular exercise is important, but living on a college campus without a car I think I get more than enough exercise walking to all my classes, walking back and forth from the grocery store, and going on a short run fairly regularly.
As happy as I was, I was still a little amazed that our energy expenditures were similar to that of hunters and gatherers. I imagined that they would be walking around everywhere on foot and doing much more physical labor than we do today. I assumed this would lead to a huge gap in energy expended between them and us, which would explain obesity. What I didn't take into account, however, was the differences in caloric intake. Even if our energy expended levels are the same, the differences in caloric intake are huge. The food we eat today is much more processed and has so many calories compared to the food of our ancestors. I think this is the main reason for obesity, not just that we don't exercise enough. We need to address this issue first and foremost before we try to start changing the exercise plans of the nation. Changing the food diet can be as simple as increasing the cost of more processed foods like fast foods which would discourage citizens to eat them. Steps like this would help move the nation towards the right direction.