Today, almost a third of U.S. adults are overweight and 43 percent have obesity. Behaviors that are likely to influence weight may be cemented early on. Early adulthood, from ages 18 to 25, is a time when people tend to experience high levels of weight gain, as young people are transitioning to adulthood and good dietary, physical activity, and sleep habits may be put to the test for the first time.
In a new study published in Nutrients , Tufts researchers determined that lifestyles during precollege years are often maintained into adulthood. The study found that, broadly speaking, people with the lowest initial level of healthfulness who maintained those behaviors into their adulthood years gained the most weight while those who maintained their healthy behaviors into adulthood gained the least weight on average.
“College is this critical window when young people have newfound autonomy and are making their own decisions around physical activity, diet, and other health behaviors more so than in earlier years,” said Dan Hatfield, adjunct assistant professor at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University and senior author on the study. ”Setting college students on a path toward maintaining or adopting healthy behaviors may have long-term implications for health and wellbeing.”
The researchers’ longitudinal study sought to test the assumption that trajectories in health behavior patterns from before college to later adult years are associated with weight-related outcomes.
To assess if and how lifestyle trajectories from precollege to later adulthood are associated with weight-related outcomes, the researchers surveyed pre-freshmen Tufts students and followed up with them 11 to 20 years later as alumni. Through these survey responses, they were able to assess how certain lifestyle behaviors changed over time and how those trajectories related to changes in weight and body mass index (BMI).
Between 1998 and 2007, 4,641 incoming Tufts undergraduate students filled out a survey indicating their intake levels of fruits, vegetables, and dairy, level of physical activity, quality of sleep, and dietary pattern (omnivorous, vegetarian, vegan, etc.). They also self-reported their height and weight along with other demographic details like age and gender. In 2018, 970 alumni from the initial group of students completed a similar follow-up survey. In typical research contexts participants aren’t reachable more than a decade after they join a study, but the university offered researchers a unique opportunity to reconnect with alumni and look at changes over a very long time horizon.
The researchers then used latent class analysis (LCA) to categorize participants in both the precollege survey and in the alumni survey into three different groups based on health behavior patterns: a healthy group, a moderately healthy group, and a minimally healthy group. Healthier groups tended to be characterized by more protective health behaviors, like higher intakes of fruits and vegetables and higher levels of physical activity. The researchers then categorized each participant into one of five different categories representing trajectories from precollege to alumni time points: stable healthy (healthy at both precollege and alumni time points), stable moderately healthy, stable minimally healthy, worsened, and improved. The most common lifestyle trajectory was stable moderately healthy (36.7 percent).
Over the 11 to 20 years between surveys, roughly half of the respondents maintained their precollege lifestyle behaviors into adulthood. Another 31.7 percent experienced worsened lifestyle behaviors while the remaining 18.6 percent improved. Two-thirds maintained a healthy weight, one-quarter switched to less healthy weight status, and less than 1 percent switched to a healthier weight status; the rest maintained stable overweight or stable obesity.
The prevalence of overweight more than doubled (from 12 to 26 percent) and obesity quadrupled (from 2 to 8 percent). However, even with those increases, the prevalence of overweight and obesity in the study sample was much lower than the national average. The researchers acknowledged that the study only surveyed Tufts students who may not be representative of the rest of the country.
These data speak to the importance of both establishing healthy behaviors in the years leading up to college and setting individuals on a trajectory to develop or maintain healthy behaviors in college years and beyond.
“Investigating the obesity question over time from different angles and demographics is crucial to moving the needle on a complex issue,” said Christina Economos , dean of the Friedman School of Nutrition Science and Policy, a co-author of the paper, and the principal investigator of the Tufts Longitudinal Health Study. “With each study like this, we build our own understanding of a condition that has vexed individuals and policy-makers alike. This latest research suggests college campuses may have a role to play with initiatives that promote healthy behaviors and improve weight-related health outcomes.”
As nearly two-thirds of recent high school graduates are enrolled in college, the study’s findings highlight the unique opportunity for college campuses to encourage healthy behaviors that are carried into later adulthood.
“College campuses can take some of the burden to adopt healthy choices off individuals by making those options easier and more accessible,” said Hatfield, who is also a senior public health researcher at FHI 360 .
Some of those campus-wide interventions might include nutrition labeling in dining halls, a la carte and trayless dining, health-themed residence halls, sleep education, and required physical activity courses, among others.
However, not all the onus rests on college campuses. The study acknowledges that while the college environment likely influences behavioral changes at a crucial period for weight management, other factors like parental influences may also play a critical role in establishing healthy habits that last into adulthood.
In addition to Hatfield and Economos, other authors of the paper include Sujata Dixit-Joshi, adjunct associate professor at the Friedman School of Nutrition Science and Policy; Peter Bakun, statistical manager at the Friedman School; Jeanne Goldberg , professor emerita at the Friedman School; Erin Hennessy , associate professor at the Friedman School; Nicola McKeown , adjunct associate professor at the Friedman School; Susan B. Roberts , adjunct professor at the Friedman School; and Gail Rogers , adjunct instructor at the Friedman School.
Nutrients
Survey
People
Longitudinal Assessment of Changes in Lifestyle Behaviors and Body Weight from Precollege to Adulthood
24-Jan-2026
The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.