tired, no weight loss, and steroids (prescription) helped

This is for my wife who is at the end of her rope.

She runs 3-5 miles a day, eats very responsibly, days yoga daily as well, and cannot lose weight.  Additionally, she is always tired, must sleep 8 hrs and that is still not enough, often naps when she gets home from work.  I, as a fairly independent observer, can affirm that she is excercising and following a great and healthy diet.  She has been this way for years.
Recently, her doctor gave her a steroid course for allergy issues (she has been receiving weekly allergy shots for 6 months) and she 'woke up'.  While on steroids, she slept 6 hrs and then was wide awake, had more energy by far than ever before, and actually lost weight.  She has had her bloodwork checked in the past and there has never been a cause discovered.  She remembers being 18 (10 yrs ago) and 30 lbs lighter.  She is making a concerted, long term effort and nothing works.  She wants this more than anything else.
Does the steroid course make sense for the weight loss and change in body?  Does it indicate what is wrong?  Why can't she lose weight when she is Actually doing everything right?

[live4fitness]

I can tell you the problem I had. I started taking the birth control depo-prevara. Most people gain weight while on it. Not me I lost 60 pounds. I got off of it and gained 20 pounds. Got back on it and now loosing again. I think that my thyroid some how got out of wack. Before your wife started the steroids did she ever have her thyroid checked? If yes did she see endocrinologist? I had hyperthyroidism several years ago and had to go see an endocrinologist to be diagnosed properly. My primary said there was nothing wrong with me. HAHAHA. They were not living in my skin. I hope this helps some how. I am glad to hear your wife is doing better. Steroids can make you feel fantastic!!!

[theonlytk]

I hope you find the answer. I had the some problem. The 2 times I had to take steroid the weight just slipped off. I had my thyroids checked before and told that nothing was wrong. I don't know who to turn to either.