Heavy use of Facebook makes you fat.

So say two researchers who found that people using social-networking sites feel so good about themselves, they lose self-control.

One of five studies they conducted found that — one healthy and one unhealthy — people who had just spent five minutes on Facebook were more likely to choose an unhealthy snack than those who had read news on CNN.com.

Another of their studies surveyed Facebook users’ credit ratings and body-mass indexes — that latter of which are a measure of obesity.

It found that those who spent the most time on Facebook had poorer credit and were more likely to be overweight.

“Greater social-network use is associated with a higher body-mass index [and] increased binge eating,” wrote Keith Wilcox of Columbia and Andrew Stephen of the University of Pittsburgh. in the report “It would be interesting to explore the persistence of the effect of browsing Facebook over time,” they wrote in the report.