Ogilvy‘s social media practice, 360 Digital Influence, partnered with ChatThreads BrandEncounter to study the impact that social media exposure had on 404 restaurant consumers. The study looked at how social media activity impacted the amount people ate, how much they spent, and their attitudes before and after the study was conducted. (The study was done at various time periods between January 20 and May 6.)

Result: Social media is one more reason why you’re fat.

The study tied a 17 percent increase in spending during the tracking time. Combining efforts can impact that result. When social media was mixed with other outreach like PR or TV, in the case of fast food chain Wendy’s, people were twice as likely to spend more than they had the week prior. In the case of KFC, it was seven times more likely.

And while exposure to social media was much less than other media (TV, for example), it had a super-size impact on changes in behavior and brand perception.

So if you find yourself gorging on “natural-cut fries with sea salt” and Frostys, it might be time to take a break from the Facebook.

The SlideShare of the study is below.