College freshmen can hold the guilt next time they order a late-night pizza.
Despite repeated warnings about packing on the dreaded “freshman 15” and rising obesity rates in the United States, a study finds that most college students do not gain 15 pounds in their first year.
"The 'freshman 15' is a myth," said Ohio State research scientist Jay Zagorsky, co-author of the study that is believed to be the first nationwide look at the purported phenomenon. "There is no 'freshman 15.'"
His research, to be published in the December issue of the journal Social Science Quarterly, found that the average student gains between 2.4 and 3.5 pounds freshman year. For women, the average weight gain was 3.1 pounds; for men it was 3.5 pounds.
“There are lots of things to worry about in college, but if you’re the average person, gaining weight is not one of them,” Zagorsky said.
Away from home for the first time, there are many reasons to fear that college students will pack on pounds, Zagorsky said. They may have access to all-you-can-eat cafeterias and high-calorie alcoholic drinks. They might not be exercising because gym class isn’t required and they may be drinking sugary caffeinated drinks if they’re tired. They may stress-eat or turn to cheap fast food if they’re on a tight budget.
Despite those changes, the research found that most kids don’t even gain 15 pounds during four years of college. Women gained an average 8.9 pounds over four years of college, while men gained an average 13.4 pounds.
The study found that few factors influenced weight gain. It didn’t matter if kids lived in a dorm or not, went to a public or private school, or studied full-time or part-time, Zagorsky said.
“In some ways people talking about the ‘freshman 10 or 15’ goes right to people’s fears. It’s ‘Oh my god. My son or daughter is going to college and is going to gain a lot of weight because of all these changes from high school,’” Zagorsky said. “I found it’s not so.”
25 percent of freshmen actually lose weight
The two factors that made a difference in weight gain were heavy drinking, which led to a gain of a little less than an extra pound, and working, which led to an extra one-fifth of a pound for each month they worked.
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And it isn’t college itself that leads to weight gain, but rather becoming a young adult. The study found that the average freshman gains less than a pound more than someone the same age who didn’t go to college.
The study also found that: Just under 10 percent of college freshman do gain 15 pounds or more; 25 percent of freshmen lost weight, and the average person gained 1.5 pounds a year in each of the first four years after college.
The study relied on nationwide data from 7,418 young people surveyed as part of the National Longitudinal Survey of Youth from 1997. The respondents reported their height and weight every year since.
The survey was conducted for the U.S. Department of Labor by the Ohio State’s Center for Human Resource Research, where Zagorsky is a researcher.
While working with the data one day, he mistakenly received a post card urging him to combat the “freshman 15” by joining a gym. Zagorsky, who also teaches economics to freshmen at Boston University, hadn’t noticed his students getting heftier but decided to check the data.
The results were surprising. “I went in assuming it was true because it had been repeated so often,” he said, adding that the first reference he found to the “freshman 15” was in a 1989 magazine article.
The study recommends that the media and colleges stop using the term “freshman 15” because, with so many people already suffering from body image issues, its continued use could lead people to suffer eating disorders, Zagorsky said.
The bottom line is that people should learn to be healthy while they’re still young, Zagorsky said, adding that even a 1.5-pound annual weight gain will lead to obesity over time.
“College is a wonderful time to learn how to eat healthy on your own, without mom and dad looking over your shoulder,” Zagorsky said. “The idea is to try to set up healthy living habits early in life.”
Lisa A. Flam is a news and lifestyle reporter in New York.
© 2013 NBCNews.com Reprints