Eating disorders are as treatable as alcohol or nicotine addiction, and as such they should be equally covered by insurance. People with eating disorders often have underlying emotional problems that need to be treated and counseling is usually covered by insurance. Eating disorders are not an illness in themselves, but usually a manifestation brought about by an underlying condition which needs treatment.
People that suffer from eating disorders die. Absolutely, insurance should cover their health care. It might save a life. As in any other life-threatening disease, insurance companies should pay for health care for them. Whether it is a mental disorder or a physical disorder or both, insurance companies should be in the business of helping save lives.
An eating disorder is a medical condition (specifically a mental disorder) which seriously impacts the person's physical and emotional well-being. It's not a "lifestyle choice," and even if it was, we spend millions (if not billions) of dollars on obesity-related health care. So why wouldn't it be covered by health insurance?
Yes, I think that insurers should still cover people who have eating disorders, because these disorders usually do not have a large effect on the overall health of someone, so will not cost to much for the insurers. Also, these people may need help if something does go wrong in other parts of their health.
I disagree with making insurance mandatory. I firmly believe that it is completely unconstitutional. However, since it is now mandatory insurers should be required to ignore all pre-existing conditions. It's not like car insurance in that people are not required by law to own a car, however, due to being alive we are required to have health insurance in the U.S. so there should be no exemptions for any reason.
Unfortunately, the way the law is written, we are required to have insurance or pay fines, but there is no requirement that we are accepted into any plans.