First, congratulations on your great weight loss! What an accomplishment. And you look great, judging by your picture.

I went throught the same thing, and I think it's just because people are used to seeing you a certain way, and it's unnerving to them to see you what in their eyes is "so skinny." In a way, they just care about you. I had to endure people pulling me aside and asking me if I was ok, after I lost 50 pounds after law school.

It sounds like you are centered and keeping your wits about you, with bringing your own food, defending your eating habits, etc.