The site's users feel happier about themselves, so they indulge. In anything.
Step away from the cookies.
Step away from Facebook first.
That might make it easier, according to a recent study by two marketing professors who found that just five minutes spent browsing the social networking site lowers self-control.
"When people use Facebook, they feel happier about themselves," said Andrew Stephen, a professor at the University of Pittsburgh who co-authored the study. "People who feel better about themselves are less likely to self-regulate. They almost give themselves a free pass to indulge in something."
The momentary boost in self-esteem, and subsequent relaxing of self-control, was strongest among those who focused on close friends while perusing the social network.
But people of all ages participating in the five studies comprising the research proved equally likely to lose control.
Facebook viewers were more likely to choose a chocolate chip cookie over a presumably healthier granola bar snack and gave up more quickly when presented with difficult math problems. Those who reported spending more time on Facebook in their daily routines were also more likely to be overweight and have lower credit scores.
Stephen said they suspect it is the repeated small indulgences that led to Facebook users' weight and financial woes.
"We have to be careful about using social media in the sense that it can momentarily affect us psychologically," he said.
From a marketing perspective, the study may be a step toward learning what type of advertising is most enticing on social media sites -- say, luxury goods over toilet paper.
But he said the research could also be useful in people's daily lives, especially if they're trying to avoid temptation.
"If [you're] about to go home and [you] want to go to the gym, don't spend time on Facebook while you're on your way," he said. "You may decide not to go."