Most people have unhealthy life styles, especially older folks who are passing their habits down to their kids. However, it is more common to have an eating disorder at a younger age. So, finding a statistic is going to be age based, and not representative of everyone.

Contrary to your question, most people that have eating disorders are not obese, they are quite likely to be unusually thin. Think: young girls throwing up after a meal. The obese people will have a problem that deals with food as a source of soothing in an emotional setting.

Most obese people have eating disorders.So 99.9 % is a safe guess!!