In my opinion, HFCS may have been one of the worse things for obesity. I have been watching some YouTube videos from The University of California, which should be a credible source. The URLs are below. As John said, the point has been made that it is hidden in so many foods. These video touch me because they are describing the process that I experienced in my life. I believe what they say.
This video is long but very interesting Sugar: The Bitter Truth http://www.youtube.com/watch?v=dBnniua6-oM
The university also made a series of shorter videos on YouTube titled "The Skinny on Obesity" Here is a link to the first video