I've been in this situation before. I worked in a minor injury clinic at a Medical Center. We wore scrubs. I had lost a significant amount of weight and all of a sudden had a very apparent bulge, which had been previously obsured by baggy fitting uniforms and love handles.
In any event, everybody was staring, including Doctors, my Nurse Manager, other superiors, co-workers, etc.
I just ignored it and accepted it. That how my clothes fit. I just thought to myself. "Oh this must be what a good looking person experiences."
Although, I have to admit it was a little unnerving when a guy would stare, particularly because, well, I was sort of a narrow minded prick at the time (Thank God for education!!!).
On occasion I would have fun with it. There was this real asshole male nurse that got his license through the Army. He was straight, had girlfriends at least part of the time and was more narrow minded that I. In anycase, when I would catch him staring I would subtly move my hips around and watch his head and eyes turn with my change of position. One time I as sitting in a chair and he nealed down to get something out of a nearby drawer. When he opened the drawer his gazed turned to my groin and he just stopped, completely mesmorized. I just stared at him until he came out his spell. When he came out of it, he looked up to see if I noticed and of course, I made very stern eye contact with him. He sort of coward away.
My recommendation is, if you are not into the idea of accepting it, to frequently asked if you spilled on yourself or if you fly is down, then looked at your groin with them with a smurk on your face. Eventually they will learn to be more discrete. Although, I have heard that "My eyes are up here" has been very effective for female friends that get a lot of unwanted attention directed at their breasts.