Rates of general stress have also increased dramatically during the past 20 years in our country and in places like Japan. People who are more stressed out tend to look for coping mechanismsm, such as eating, to aleviate their stress. Your example about going for a 10 mile run versus hitting the local KFC is poor. 99% of people are not runners, and it would not occur to them to go for a 10 mile to deal with stress as it might occur to you. Also, exercising isn't always the best way to deal with problems either. It might make you feel like the better person to run 10 miles, versus hitting up KFC, but the reality is that you are also looking for a way to avoid dealing with your problem by running instead of getting to the heart of your problem. Many people become anorexic because they try to cope with a tragic event by exercising. It is a control issue.
And, I will say it again. If you have a food addiction (a chemical problem that you don't decide whether or not you get), eating tons of food is not a "lifesytle decision," it is something you do without any control knowing that it is ruining your body, and it is something you do feeling incredibly lonely and depressed. Its like being an alcoholic or smoker, expect you had a choice wheter or not to start drinking or smoking, but you didn't have a choice in whether or not to start eating.