Exams, study halls and stinky dorm rooms—sure those are all not-so-fun aspects of college life. But let’s be honest, the most frustrating near-promise of that first year away from home? The Freshman 15.Blame all that late-night pizza. Or the stress of school and missing home. Or, you know, the fact that high-school sports give way to co-ed keg-stands. Whatever the reason, those first-year pounds are as predictable as they are pesky—with thousands of students struggling to tug on their skinny-jeans by second semester—and new research says it’s even more predictable than previously realized.QUIZ: Are You Eating Pretty? Led by Dartmouth College, the latest research used brain imaging to examine the role that brain reward regions might play in freshman weight gain. The method was simple yet clever: Nearly 50 first-year female students were hooked up to an fMRI (functional magnetic resonance imaging) and then asked to look at photos and note whether there were people included in the photo. The secret? There were food cues embedded into some of the photos, even though the subjects didn’t realize food was the study’s focus at all.The inherent question then: How would each person’s brain respond to the cues, and could that predict who was likely to gain weight?The results were fascinating. Nearly every student in the study showed at least some reward response when they ogled the food photos (no surprise there, who doesn’t love to eat?), and the students gained an average of seven pounds in the following six months. The big kicker, however, was that the more the subject’s brain lit up during the food photos, the more weight they gained over that next half year.A likely reason behind it all? Control issues. Todd Heatherton, lead researcher of the Dartmouth study, hypothesizes that freshmen who are more “wired” to respond to food (like say, that beckoning buffet-style dining hall) will find it more difficult to control their food intake.MORE: Skincare for College“It could be that some people gain weight because their brain reward regions are hyperresponsive and so they are easily tempted, or because they don’t have adequate self-control,” he said. “Our research is trying to answer this question in order to figure out how to help people not give in to temptation.” (Whoever cracks that code, hats off to you.)What’s still unclear is what the Freshman 15 means for the rest of someone’s life, Heatherton says. Yes, the data shows that certain people respond more strongly to food cues—so we know who is more likely to reach for that milkshake or second cookie—but is that weight gain likely to continue throughout their life? Or is it unique to college?MORE: Can Personality Predict Weight Gain?Only more research will tell. For now, evidence does suggest that willpower—as assessed when children are very young—can predict how a person will regulate their behavior in adulthood. So perhaps self-control is still the main player at any age, whether it’s four or 40.“Other studies show that better self-control as children leads to better health, higher incomes, and fewer problems across many life spheres in adulthood,” Heatherton says. “Thus, it could be that some people have weaker control systems, for whatever reason, and this leaves them prone to self-regulation failure.”So, the next time your relatives hint that you’ve packed on a few when you’re home on break? Just impress them with your new science smarts. “Oh, it’s just my brain’s intelligent reward system, adjusting to my tempting new college environment!” Then, hit the campus gym and study up on some new healthy eating habits, stat.QUIZ: Do You Fat Talk ? Find Out for a Better Body Image.