I haven't told anyone except my husband and it's been a complete non-issue. My coworkers sometimes tease about how little I eat, but I work with all men, and they're big guys. They know I'm trying to lose weight, trying to be careful about what I eat, and that I'm physically way tinier than they are (even before surgery). I don't let their teasing bother me.
I do think twice when ordering at restaurants. The portions are HUGE and it does end up seeming like I didn't like my food or just picked at my food. When my husband is with me, we'll share his meal and I'll get a soup or side salad. Friends/family who eat with us just think we're being cute, it doesn't occur to them that I've consumed a considerably small amount of food. When I'm by myself, I'll look for something that seems like it will be on the smaller/lighter side. I avoid things like salads because I can't eat to make even a dent in the salad, lol. I'll usually do something like a single taco plate, or a small protein (chicken) with side veggies, etc.