Growing your circle of friends could shrink your waistline.
When mice were moved from an environment where they had few pals to one they shared with 15 to 20 rodent roommates, they shed 50 percent of their belly fat within four weeks, reports the journal Cell Metabolism.
Somehow the more engaging environment caused white fat – the stuff that causes pudge – to turn into brown fat, a type that burns calories. (Humans also have both kinds.) More research is needed to determine why this happens, but stepping up your social life might pay off on the scale.