I don’t know whether High Fructose Corn Syrup (HFCS) acts more like fat than does sugar (compare here and here) but it’s worthwhile pointing out that HFCS is a child of the sugar quota. The import quotas raise the US price of sugar well above the world price (~24 cents per pound compared to ~9 cents per pound) and encourage consumption of HFCS. Reflecting this fact, the main defenders of the sugar quota are no longer Florida sugar growers but rather mid-West corn growers.
The HFCS business is a cartel – prices are the same, change quarterly on the same day and enjoy, as Tabarrok points out, subsidies. Years ago, working in the water and juice industry, I sent a letter to the anti-trust division complaining about this. A lawyer deep in the bowels of the justice department phoned me and said that “as long as Bob Dole is active on this issue, nothing will change”. I assume someone has replaced Dole as a friend to the corn processors.