I've been following the Junkfood Science Blog for a couple years now and have learned a lot about the science of obesity. Most of the real science and valid clinical research buck the "conventional wisdom" or "common sense" that people spew forth on a daily basis. We are constantly bombarded with crap about health weights, BMIs, good food and bad foods. Unfortunately, people are as apathetic about their health news as they are about their politics. Whatever the favored talking head says in the 30 second sound bite is good enough for most people. Well, lucky for us, science doesn't survive on sound bites.
Given all that, I was pleasantly surprised when I saw this story on one of my favorite programs: Nova Science Now! They interview a couple leading scientists that are studying obesity. These scientists have proven research to indicate that some super fat people have genetic anomalies that prevent them from feeling full. Certain receptors in their brains are unable to receive the proper chemical triggers that signal their brain that they are full. This is only one genetic reason for obesity. They do go on to say that the most important factor that determines the shape and size of our bodies is our genes.
Don't take my word for it and don't rely on one blogger's report either. Do your own research. Look for independent sources. Read the studies.