Yep, this study is fundamentally flawed. Surely they could have found at least one statistician who knows, inter alia, the difference between cause and effect?
Overweight? C'mon, 80% of the US population is supposed to be in the overweight to obese/morbidly obese range (I'm from Oz- we're supposed to be around 60%... and a bridge was closed today to allow for a rescue by crane of a 300 kg man from his apartment above the bridge because he had a chronic asthma attack).
Oh well, I'm sure the tabloids will have some fun and one or more ambulance chasers will go after a gaming company on the basis of this study. Other than that, the document belongs in the fantasy section of my book collection.