AUBURN, Ala.—An Auburn University study that tracked changes in male and female college students’ weight, size, shape and body composition not just as freshmen but over the course of their four-year college careers indicates that students are heavier and, yes, fatter when they graduate than they were when they first arrived on campus. And that’s true more so for the male student body than the female.

Results from the in-depth research project that ultimately followed 89 females and 42 males from their first semester on campus in August 2007 to their last in May 2011 showed seven out of every 10 students participating in the study gained weight—an average of 13 pounds for males and 3.7 pounds for females—on their journey to a bachelor’s degree.

More telling, however, were the changes in body fat percentages, which revealed that the average weight-gaining student in the four-year study had 4.7 percent more fat tissue as a graduating senior than he or she had as an incoming freshman. Body fat percentages increase not only with gain of fat tissue but also with the loss of lean muscle mass, so, although females in the study gained only 3.7 pounds on the scales, they had 8.5 more pounds of fat in the body at the study’s end. For males, the higher body fat percentage translated into 11.1 pounds of fat.

“Most of the handful of studies that have been done on college weight gain have focused only on female students,” says Auburn nutrition professor Sareen Gropper, who, with consumer affairs professor Lenda Jo Connell, led the team of Alabama Agricultural Experiment Station scientists involved in the longitudinal experiment. “But from our data, the gains in weight and body fat suggest increased health risks for many college males.”

The same could be said for the changes in participants’ physiques over the four years. Using 3-D body scanning technology housed in Auburn’s College of Human Sciences, the research team, which also included consumer affairs faculty Karla Simmons and Pam Ulrich, was able to track where those who gained weight were gaining it. The body scan images revealed that, for male weight-gainers, the extra pounds were most likely to show up in their waists and, for females, in their thighs and seats. The waist is considered the unhealthiest place to add fat.

Males also had a more significant increase in body mass index, which is calculated based on height and weight. For males, the average BMI increase was 1.8 kilograms per meter squared, compared to 0.6 in females.

In the study’s first year, the Auburn researchers did examine the Freshman 15 phenomenon—in which they found that first-year college students at Auburn gained an average of only 4 pounds instead of the legendary 15—but the overall multidimensional investigation that Gropper and Connell led was unprecedented in its scope to track changes not only in body weight, size, shape and composition changes in both female and male college students over four years but also environmental, behavioral and psychological factors associated with these changes.

“We looked at whether they lived on campus or off, how much they exercised, whether they typically ate alone or with others, where they ate, their sleep habits, their stress levels, their self-esteem in terms of body changes, whether they would lose the weight they’d gained in the school year over the summer—a broad range of factors,” Connell says.

In that freshman year, for instance, students who resided on campus gained more weight and body fat than those who lived off campus, but Connell says the choice of dining options may have contributed to that.

“At that time, the campus dining halls had all-you-can-eat night, and some freshmen may have made the most of that,” she says. “And, most those on campus tended to eat with several people at each mean, and our findings indicate that those who usually ate with two or more friends gained more weight and fat.”

Initially, 240 freshmen—156 females and 84 males—signed up for the study, which required them to report for data collection three specific times in their freshman and sophomore years and at the beginnings and ends of their final two years. Students did receive stipends over the course of the project, and for many of them, money was their key motivation for sticking with the study, Gropper said.

Though 45.5 percent of the original participants dropped out along the way due to such factors as transfers, early graduations, academic suspensions, pregnancies, marriages and broken legs, Connell says the 54.5 percent retention rate from start to finish was outstanding and yielded a wealth of scientifically sound information that can be used in structuring intervention and educational programs for college students.

“Note that 30 percent of the students in the study did not gain any weight while they were in college, and in fact, the females who reported doing strength training consistently actually lost weight and lost body fat,” she says.