According to a recent Star Magazine article, Mary Kate Olsen has dropped weight again, down to an estimated 80 pounds. With that comes the speculation that she is suffering from an eating disorder and has relapsed since seeking help in 2004.

There is evidence that Mary Kate did enter rehab in 2004, but no medical professional or Olsen family member has ever come out and said "Yes, Mary Kate is suffering from an eating disorder." Certainly, this famous twin is skinny. In 2004, she looked downright boney and, physically, appeared to have an eating disorder.

There are a number of eating disorders that could result in dramatic, unhealthy weight loss. Classic anorexia is a condition where an individual eats as little as possible or exercises obsessively. Another form of anorexia is binging and purging; where an individual still restricts their caloric intake but also forces themselves to vomit. Bulimia is a condition where an individual will eat whatever they like, but induce vomiting soon after eating.

So how do you know if someone you care about has an eating disorder? There are a number of symptoms associated with these conditions and many of them are easy to spot if you know what you're looking for. The most obvious symptom is, of course, dramatic weight loss. Individuals will begin too look boney, with hollow cheeks and sunken eyes. They may also seem tired or weak and may experience hair loss. If you noticed any of these changes in your friend or family member, along with an obsession with dieting and exercise, contact a doctor immediately.