College students may not gain the much-dreaded "freshman 15" but they do gain weight during their years in school, according to a fresh look at some past research.

Young adults gained an average of about 3.5 pounds (about 1.6 kg) over their college careers with a relatively small gain during the first year, researchers found.

“Everyone puts so much emphasis on at first year of college,” said Michael Fedewa, the study’s lead author from the University of Georgia in Athens.

“But what we found from this study was the change in weight and body fat during the first year continues on and so we think that change in weight and fat is related to time more than anything else,” he said in a phone call.

The longer students were followed, the bigger the change in weight, Fedewa said. Also, the weight gain seen among college students was similar to what other researchers have observed among young adults not in college.

“I don't think it's something that’s just limited to college students,” he said. “I think it happens to everybody during those late adolescent and early adult years.”

For the new study, published in the American Journal of Preventive Medicine, Fedewa and his colleagues gathered data from 48 earlier studies that examined changes in weight and body fat among young adults.

The studies were mostly conducted in the U.S. and followed young adults for anywhere from 1.5 months to four years.

The college students gained an average of about 3.5 pounds during their four years of school and experienced about a 1.2 percent increase in body fat, the researchers found.

“We were surprised at how little the weight gain was,” Fedewa said. “We thought we would see a lot greater weight change because the ‘freshman 15’ is this big scary number.”

The "freshman 15" refers to the amount of weight many college students in the U.S. and Canada are traditionally rumored to gain in their first year: 15 pounds, or close to 7 kg. Other countries have different terms for the same phenomenon.

While a few extra pounds is relatively small compared to the dreaded "freshman 15," the researchers say young adulthood may instead be a “tipping point” in lifelong behaviors related to weight management.

David Levitsky, an expert on weight management at Cornell University in Ithaca, New York, told Reuters Health in a phone interview that college may create an environment that encourages weight gain. Factors include vending machines, late-night studying and all-you-can-eat meal plans.

“The problem with that is that there's lots of data showing the more food that you put on the plate, the more you're going to eat, said Levitsky, who was not involved with the new analysis.

“(But) it's not just the college kids that are gaining weight - all people between 18 and 40 gain weight and that is the major contributor to the obesity problem we have,” he said. “So these factors in the university that are coercing these kids to gain weight are the same factors that are in the outside world forcing other 18 to 40 year olds to gain weight.”

Fedewa said that college campuses are designed so that students can walk or ride their bikes to class.

“Trying to figure out how to get more physical activity in your everyday life by just moving more on your own would definitely prevent some of that unnecessary weight gain that happens to some college students,” he said.

Levitsky also suggests daily weight tracking as one of the most important factors in controlling weight.

“If you see yourself going up a pound or two, it's pretty easy to reverse that in about a week,” he said.

Losing weight becomes more difficult when a person doesn’t look at the scale, their pants don’t fit and they realize that they’re 10 to 15 pounds heavier, he added.