No, I don't think you should MYOB in this situation. Would you mind your own business if your friend was bingeing and purging everyday? Would you mind you own business if your friend had developed a problem with drugs or alcohol? What your friend is doing is dangerous! This can be life threatening. No, I don't think calling her doctor would result in a positive outcome, however, I dont think you should leave your friend hanging either. I guess it all comes down to your interpretation of friendship.

I would strongly encourage her to discuss this with her doctor. If she refuses I would call the doctor. The doctor is not prohibited by HIPPA from listening to your concerns. Any decent doctor will discuss them with your friend. You can ask the doctor NOT to mention your name.
Worse thing that can happen if you intervene? Your friend may find out that you care enough about her to try to help.

Worse thing that can happen if you do nothing? Your friend may suffer the consequences of such drastic starvation (electrolyte imbalances, heartbeat irregularities, and even death) or she may be very lucky and just suffer when she regains the weight.

She is lucky to have you as a friend!

I find this a bit harsh. I'm not claiming to be an expert. If I was an expert I'd be at my target weight and would never have been overweight.

That said, thanks everyone for the advise. I think I will forego calling her dr. It's true, she may listen, but then again, I'm not her patient.

Hopefully my friend will find that getting weaker and weaker is a result of not consuming enough fuel. I don't know how she goes to work everyday and maintains a spotless home with such a lack of food.

Like you all said, it's her body and mind. I'll just tell her that I don't back what she's doing if she calls again to complain about being tired. I will back a sensible eating plan and look forward to some bike rides.

Thanks again everyone.

I'm a bit concerned that she may not tell the doctor what she's doing, or the extent of it. Those of us with disorders of one sort or another have been known to kind of fudge things a bit to keep "official" people - like doctors - from getting concerned.

I'd probably call the doctor - just let him know what's up, ask him not to mention your call. Would you rather your friend get the help she needs and be mad at you, or destroy her body slowly and think you're supporting her?

By the way, I'm with the "MYOB comment was rude" camp. No need to be harsh like that.

You're right to be concerned but I agree that you shouldn't call the doctor. When she's put back on all of the weight she lost and more besides she may decide that you were right. Nothing more you can do.

I had considered medifast, which is a 800-1000 calorie diet and I have more than 75lbs to lose. The big picture your friend is missing is that while she will lose the weight, the revenge will be she will, no doubt about it, screw up her metabolism making it impossible to keep it off and requiring her to live on fewer calories. I feel sorry for her and would intervene as a friend too. However, it's not in any way shape or form appropriate to talk with her doctor. You can only give her advice that sinks in.

"Friend, if you do it this way, this IS what will happen, you realize that right?" Let her make the decision for her, but fully armed. You can arm her....