How is body-image culturally constructed?

Body-image is a very touchy subject in America because, as Michael Rosenwald points out in his article "Why America Has to Be Fat", two-thirds of Americans are overweight. Body-image is not usually constructed by us, but by others. It is constructed by people who are in charge of what we watch, read, and do. This includes models, magazines, tv shows, movies, professional athletes, or just about anyone we could see as an example for how we are to live our lives. It is common knowledge that teenage girls want to look like the models in the magazines, and those models are unnaturally skinny and most of them have eating disorders. Yet this is what the industry uses as role models for vulnerable people. In addition, family members and friends can have a large influence in how someone feels about their body-image. I know I have had friends whose parents told them they were fat when they were already really skinny. Friends could also tell someone something playfully, but then they could take it the wrong way and try to fix that part of their body.
Everywhere you look in America, you will see an ad or show that stars a thin, beautiful person while most of America is becoming overweight. By having this "nationally accepted" body-image, most common people, who are most likely overweight, spend lots of money on dieting and gym memberships. This helps bring in revenue to the companies, even if they are never used by the consumer. The food industry also takes advantage of this trend by going against this type of body-image. It does this by producing meals and products with more calories and fat were produced few decades ago. This goes against the "tall, thin, and tan" idea that most people believe is the ideal body image.
This image holds true for people of most all ages, but it is especially true for younger people who very often may judge people on how they look. I have found this to be true at college and all during high school. My surprise in how America values looks and body-image came when my brother started middle school just over two years ago. When I was in middle school not so long ago, people weren't dressing very risky and constantly switching between boyfriends or girlfriends. Granted, some of the students were like that. But after picking up my brother every day after school last year and getting to know some of the other students there, my opinion on that age has changed. Students those age place a lot on their appearances. This is due mostly to society and what magazines and tv shows, especially on Disney Channel, have taught them to believe what is "cool".