Fit-4-40,
I didn't see the Dr. Phil show, but wanted to pop in and tell you, you aren't alone. My DS came home from 1st grade w/ a new awareness about "bad" food and fat/thin people. This education was on the bus and playground, unfortunately, and not in the classroom. He then started pointing out all the deemed "bad" and fattening foods wherever we were. Until this point, he had never noticed a person's size.
I could see he was becoming concerned for himself (and his sister, a year younger, would point out if she was eating a cookie or a chip), so the next time he made a comment I asked him if he was afraid of becoming fat and why (mind you, he is a string bean, wears a slim and they hang off him, his sister, too). He said he was, because then no one would like him. I continued by asking him what healthy food are. He listed a bunch a fruits, veggies and meats. "Do you eat a lot of those foods," I asked. "Yes," was his answer. I followed up with by asking him what he considered bad foods. Tied the conversation together by pointing out he ate far more healthy foods than treats--I won't call them bad foods. I am teaching them they can eat anything as long as it is in moderation and they've had their healthy foods first.
I also talked with him about exercise. Both kids do karate and swim. He would ride his bike 24/7 if we allowed it. Our DD also dances. Pointed out what Mommy and Daddy do for exercise. We concluded that our family lives a healthy lifestyle and we shouldn't worry too much about the size of our belly because of it.
I also emphasized he shouldn't judge a person by their size. We happen to have a close family friend who was in a car acident and suffered a head injury. The Drs haven't been able to find a medication that regulates her hunger and she has gained about 150 lbs. I asked him what he would think about people who call her names--and, sadly, there are many. He was appalled.
To make a long story short, I think communication is the key. And, leading by example. If we obsessive over the size of our thighs, the kids will notice.
Kerilyn