The Issue of Body Image

Do you ever wonder why parents lie to their children? My parents lied to me when they taught me to respond to kids teasing me with, "Sticks and stones may break my bones but names will never hurt me." As an adult, I've learned it's often less painful to fall down a set of stairs than it is to experience someone directing a hurtful comment toward you. There are times when you know the person wasn't intentionally trying to hurt you with their words but even in those situations it is still really difficult to not feel badly because of what they've said.
The reason this is on my mind is due to a conversation I had with a school acquaintance yesterday. He's a little younger than me and he's not American so possibly something was lost in translation but the conversation went like this:
BOTH: Verizon vs. T-Mobile; blah, blah, blah. New Motorola phone; blah, blah, blah.
HIM: Can I tell you something?
ME: Sure.
HIM: You have really gained weight.
ME: (flustered, embarrassed, angry) Um, yeah, well I haven't had much time to work-out lately.
Immediately following this conversation we were attending a department holiday party where I found it impossible to take more than two bites of any food there because I was worried he was watching and judging me for eating. The rest of the day was pretty sad for me and today I am not feeling much better. One half of me is angry at his inappropriate commentary on my body and believes he can't see clearly because I have actually lost weight over the last 6 months. The other half of me is devastated and incredibly insecure because a near stranger basically informed me I'm fat. I can't help but think if he thinks so then others must share his opinion. I'm not sharing this to fish for compliments or assurances about what I look like. I'm sharing this to continue the recent body image conversations the public and my friends have been having...
The other week I was home, trying to study, and I happen to catch a few minutes of the Tyra Show. She had a guest who hates herself because she believes her body is ugly. As I was watching that show I realized I was able to completely identify with Tyra's guest and I, too, do not like my body very much. It's worse, lately, because when I ran out of time to study/work/sleep exercise was the first activity I was willing to cut out of my schedule. So, just like that I become my own worst enemy by allowing myself to make exercising a lower priority; therefore, I perpetuate my poor self-concept of my body image. Tyra made a life size cardboard cut-out of her guest in a bikini - she didn't airbrush anything or make any changes in any way to this woman's body - and then they (show employees) took the cardboard cut-out to the streets to solicit the public's opinion about this girl's body. Everyone said she looked great or healthy or beautiful...including me. So, my question to you: Why can't we look in a mirror and be happy with what we see?