Recent news attributes nations weight gain to excess food, not lack of exercise

Recently in a paper presented at the European Congress on Obesity, researchers attributed weight gain in America solely to the increase of calorie consumption and not lack of exercise. Article While this study clearly shows that we are consuming too many calories I really hope it doesn't dissuade individuals wanting to lose weight from also starting a good exercise program.  Consistent exercise has been shown to be a key in disease prevention and longevity.  So what do you think about the study?