Social media―it can help you keep up with friends, stay on top of the news, and maybe even fit into your skinny jeans. Because a study shows that using Twitter can help people lose weight. The results appear in the journal Translational Behavioral Medicine. Now the volunteers in the study were taking part in a media-assisted weight loss program. For six months, 96 overweight participants tuned in to weekly podcasts about nutrition and exercise. In addition, half of them made use of mobile apps to track calories and physical activity, and to keep other folks in the study apprised of their progress. On the whole, participants reduced their body weight by about 3 percent. But those who used Twitter lost even more: another half a percent for every 10 times they Tweeted. Some Tweets offered emotional support, but many were simply informative. Like, “Avoided the pastries at this morning's meeting. But I did have a skim mocha without whipped cream.” Such confessional Tweeting may help dieters stay honest. Or at least keep their fingers occupied and out of the cookie jar.