How fast is it possible to lose 42 lbs?!

How fast is it possible to lose 42 lbs?

I'm not looking for an answer saying 'that's not healthy', but a 131 lb (9st5) person wants to be 90 lbs (6st6), with an eating disordered history, how quick might that person be able to lose that much? Best answer will be given.

I can't believe people that have answered your question. You could die if you get that weight. You mentioned you have a past of eating disorders, so do I. I was anorexic when I was 13, and got hospitalized. I had people watching me 24/7, and forcing me to eat when I didn't want to. They would also follow me to the toilets in case I was to make myself sick. It is a horrible world, and anorexia MAKES the horrible world - it is a horrible memory that makes me sick to my stomach at the thought of it all. I am now a healthy 19-yr-old, working at a gym, being people's personal trainers and running dance classes every Thursday for young teenage girls. I am happy and my weight doesn't bother me. I do lots and lots of exercise each day, but I eat the right foods, too - I don't starve like I used to and I don't throw up my food. I eat what I want, when I want without having to worry how to burn it off. It is very easy nowadays, my weight never bothers me, and I don't even own a pair of scales - the only scales I have are at the gym. My message to you is, don't go down that long, painful trail of anorexia again - you can do ALOT better than that. You could die from your disease and think of how your family will feel. They will be rattled with guilt for the rest of their lives. Please get help now, while you still can. I hope you are okay sweetie. Please listen to what I have written down. x