Americans are fat because they only eat hamburgers

It is a commonly believed here that Americans are fat and that they eat hamburgers everyday. Thus the reasoning is that if Americans eat hamburgers and Americans are fat then hamburgers must make you fat. It's hard to convince anyone that hamburgers aren't any more fattening then some of their heavily fried foods or to convince them that Americans eat many different types of food. Then the other day I was reading a story from my students' lesson book and this is what I found.

Are They Healthy?

This is Sally. She likes vegetables. She has vegitables everyday. She doesn't like soda or hamburgers. Sally is very healthy. (then they had a picture of a thin girl)
This is Tom. He doesn't like vegetables. He has hamburgers, fries and soda every day. Is Tom healthy? (then they had a picture of a really fat boy)

Doesn't it sound like a stereotype? No wonder it's so hard to convince people otherwise. They're trained to believe hamburgers are the reason for people being fat. One of the teachers even told me that in America you can see a fat man eating hamburgers around ever corner. I honestly think he's gotten it all wrong. It's fat men eating twinkies and donuts on every corner. ;)