It's a concept movie. The reality is that people prefer lies to truth (not Bill O'Reilly's "truth") and thus "changing bad habits to good ones" will always be an uphill struggle. People eat fast food because it tastes good and is easy to get as opposed to buying healthy food from a fresh market and putting the work into making something healthy. The natural stress and constant atrophy of life makes the struggle to be healthy even harder and often one is still left feeling hungry and emotionally unsatisfied even after making healthy changes similar to fat people who are truthfully trying to lose weight but see no real substantial results after long-periods of diet and exercise. Eating fast food is like caving in to any other addiction, it serves to fill a deep seated dissatisfaction with existence - it is short-term pleasure for long-term pain. The argument here is that there is no point to being "healthy" if all other facets of your life are falling apart. Society is a fragile system of conformity and people take pleasure in other's pain - that is the nature of the competition for survival. Until humans can re-structure the way they experience reality and "desire" healthy living than no change in society will occur and the market will continue to cater to our deep-rooted addictions and, passively, we will submit despite watching ourselves destroy ourselves.