Well, for me it isn't noticing. I'm an event planner (among other things) and support about 160 people. I don't see most of these people more than once a year. Heck, I don't recognize most of them we see each other so infrequently! So they definitely wouldn't be the type to notice a change in my eating habits.
I'm slowly telling friends about my decision, but I think I will refrain from coworkers unless asked directly. I'm coming around to the fact that this is a tool and just like using a crutch isn't shameful, getting this surgery isn't either. Unfortunately, I've had a few people with really unsupportive reactions. I'd rather not have to deal with that at work too!