This paper is primarily a report on the results of infecting rats with Ad-36. Other people, jimrandomh in particular, have already mentioned it. I mention it here, not because of the results it reports, but rather because of this fascinating introduction:

Although obesity is associated with several health risks, not all obese individuals are adversely affected by it. To better utilize health care resources, it would help immensely to selectively target prevention and treatment efforts by identifying “at risk” individuals from those who are relatively protected from the adverse effects of obesity. Recent emerging evidence from animal models and human studies indicates that some forms of obesity may indeed carry relatively low health risk. We reported that human adenovirus Ad36 infection appears to be one such marker of “low risk” obesity. [snip summary of evidence] Thus, Ad36 induces obesity with metabolically favorable profile in animals and is associated with such obesity in humans.

I'm not sure whether this makes the Ad-36 hypothesis less important, or more important. If a sizable fraction of obese people can stop worrying about the long term health effects of their condition, isn't that a Good Thing?