A couple of recent posts regarding food addiction that are worth reading. Here's one from Jeff with a well-written article by his dad and his view on things. Also Matt Metzgar has been discussing this topic also here.
Personally, I think that there are addictive components, both physical and mental to eating refined and processed foods. As a society, we're brought up with it with sugars, sweets, and treats for every occasion such as holidays, birthday parties, celebrations, etc. Kids are brought up from the get-go with high sugar cereals, 'fruit juice' boxes, etc. Then into adulthood, as the obesity epidemic marches on, the wrong solution of low fat, watch your calories provides a misleading answer to a problem started in our youth.
Not to sound like a Puritan. Do I enjoy a chocolate chip muffin? Heck yeah. But I save it for a rare treat. Seems like the general population eats the wrong foods as the mainstay of their diets and they are unable to break that habit.