>>403537701. companies trying to integrate their products into culture has resulted in an arms race of fattening commercial products that have now entered into the family unit, creating "fat families", whose children are made fat from a young age
2. the ease and availability of horrendous dietary choices, again linked to the commercial arms race of food
3. the obsession with wealth has led to a society where work is not only a primary focus, but usually THE primary focus. Adults will sacrifice their child's wellbeing and their own personal health, for work. As such, a burned out adult will not desire to come home and cook, when it only costs like $10 for some fast food for them and little Jimmy
5. the natural progression and spiraling out of control, of English (and by extension) European eating habits. This comes in with the desire for meats, many of which are very fattening and very available
6. culture. Being a fledgling country in its early years, America never really had time to establish a large background of good dietary habits, like a country such as Italy.
7. environment for exercise. Not only is the average American stressed and overworked, but they also don't relieve that stress through exercise. One cannot exercise simply by walking to work, or walking to an ice-cream parlor or what have you. Due to the urban nature, or the very disparate rural nature of most of America, transportation is almost solely done by car. If you live in an average American city, having at least one car in your family is a requirement. So an average American drives to work (sitting), works at an office all day (sitting), then is overstressed and exhausted, so they drive home (sitting), buy fast food or some other cheap and easy but unhealthy food, and then watch TV before falling asleep.
Speaking as an American who comes from a particularly non-American city (Miami), and whose girlfriend is from rural Illinois, I feel fairly qualified to speak on the state of American obesity.