90% (just a guess could be 70%, 80%) of the western population is "ADDICTED" to cheap carbs. Most people are drawn to carbs more than just choosing to eat it, just look around, yes the fat does alot of damage to your waist line but its the carbs people are drawn to. I posted earlier in this thread that our brains are fueled by glucose (carbs) and in nearly all SAD dieters the brain compelles them to add a new hit of carbs every few hours instead of doing some metabolic magic and converting it from other sources.
Look at the Carb Flu why does nearly everybody that comes over from A SAD diet get it. because the carb flu is a addiction response to not getting your hit of carbs.
Carbs get you addicted to the fast food, both the fat (tastes real good) and carbs do the damage to your waist line. The addiction leads to a big calorie surplus and then we have an obesity epidemic. The big food companies aren't stupid you know, they know how it works.