From the sounds of it, I would say the woman who did this to you is insecure with herself. You stated she's heavy. Odd as this may sound, by her trying to belittle you in front of your other co-workers (who I'm sure were also partaking in the treats), her intention was to get the others to join her. It backfired on her. When others are insecure they try to make themselves feel better by negatively commenting about something another person is doing that they wish they themselves could do. Take it with a grain of salt...you handled it very well