So I have this friend (really, I do). After she indulges in a piece of chocolate, she’s able to save the rest for later. Like, successfully. Then there’s me, who thinks nothing of eating an entire box—then shamelessly finishing the rest of hers. Sound familiar? If your self-control is M.I.A. during battles between you and your cravings, there’s a new lead as to why.Some people are simply more likely to fail when it comes to self-regulation than others, say Dartmouth College psychologists Rich Lopez and Todd Heatherton, Ph.D. Their research shows that varying levels of activity in areas of the brain related to reward and self-control may help predict who can resist temptation, and who’s bound to give in.In their April 2014 study in Psychological Science, Lopez and Heatherton focused on two areas of the brain: the inferior frontal gyrus (IFG) and nucleus accumbens (NAcc). The NAcc is a central player in the brain’s reward system—a hotbed of gimme gimme activity—while the IFG is essentially your parental controls: Rapid firing in the former means you’ll practically make out with that cupcake you’re eyeing, while greater activity in the latter will put the kibosh on a chocolate-frosted binge-fest.Thirty-one female participants took part in an initial brain scan. During part one of the scan, the women were shown a variety of images, some of which were of high-calorie foods—desserts, fast-food items, snacks and the like. They were asked to answer arbitrary questions about the snapshots while researchers sneakily measured NAcc activity. In part two of the experiment, they were again shown a variety of images and had to press a button after seeing some of them and fight the reflex to press the button after others, allowing the researchers to measure inhibitory IFG activity.For one week after the brain scan, participants were signalled several times a day via smartphone to report their cravings and eating habits. When they reported a craving, they described the strength of the craving and their resistance to it. When they surrendered to a craving, they reported how much they’d eaten.As expected, the women with higher activity in their reward center had stronger food desires. They also gave in to their cravings more often, as did women with low IFG activity, who were eight times more likely to cave than their high-IFG counterparts. Not only were the high-IFG group better equipped to resist their cravings, but they also managed to eat less when they did indulge.When Lopez looked at the participants’ self-reports of their ability to resist temptation compared to the brain scan data, it was clear to him that “people are not necessarily consciously aware of how sensitive they are to rewarding cues in their environment. How we can make people aware is an important avenue for future research.” Studies are now being conducted in Lopez’s lab to see if it’s possible to train people to improve their self-control capacity using techniques derived from cognitive behavioral therapy.In the meantime, if you have a hunch your IFG isn’t firing on all cylinders or your NAcc is pressuring you to pig out, there are several things you can do to turn on your own parental controls. First, learn what might be causing your cravings, then replace your go-to snacks with healthier alternatives. (Yes, this even works for all you stress eaters out there.) And if you really want to get the upper hand on your sweet tooth, be sure to get a good night’s sleep (every night), as sleep deprivation is like a kill switch for self-control and makes you crave junk food, to boot.MORE: 10 Surprising Signs of Sleep Deprivation