It depends over what period of time to lose it as to whether or not it is healthy.
I have not changed jobs recently but changed shifts to a more actively involved shift, that I am moving more, walking, and standing, no sitting anymore and less just standing around. I lost a considerable amount of weight in just a few weeks. I happen to have a recent visit with my doc for a check-up, and he said this was to be expected with the activity changes at work. If it continues to a point we designated and/or if I develop other symptoms, to definitely let him know.
I also know with the stress of this new position that I have not been eating as much as I used to either. I have lost some of my appetite. This has played a factor as well. So between the reduced calories and increased exercise, it is not surprising.
If concerned or cannot explain why this is happening and/or have even developed other symptoms, I would recommend contacting your physician and talk to them about it and let them know what is happening.
Good luck with your job; stay healthy.